Hi Amir,

I think heat pump/split system could be a selling point if it is part of an overall home energy use strategy (that would include things like solar, air sealing, insulating, HRV, etc.). Ask a realtor?

We are in the next county north. We have a heat pump. Our annual PG&E bill is comparable to what we used to pay for a smaller space with gas furnace heat. I think the primary factor keeping bills down is that the new house has much better air sealing and insulation.

Good luck!

Elmer - just to be clear. Minisplits do not have backup electric strips. There is no reason in the Bay area to think that backup electric strips would ever be needed.

I ran some numbers and it is about 25% more expensive at your high tiers to run a minisplit even at mild temps. Obviously not a good choice. But at $.28 a kwh and federal tax credit, solar pays off fairly quickly if you have a good roof for it. Should be a sub 10 year payback but "should be" makes a lot of assumptions about your local install cost.

Ok....I think Mike and I both missed the dismal point in what Amir first posted for elect. 10.1kw is very reasonable.

OP....what has the crawl space and attic have to do with heat/cooling????????? Are neither insulated??

The plan is to put units in the Attic and crawl space.

Yes, attic and crawl space install locations are common in this area. Also, sometimes in the garage or in an interior closet that's vented to outside air (usually small screened openings on the floor to the crawlspace and at similarly on the ceiling open to the attic. I think that's a code requirement. Also, the metal exhaust stack to the roof (for an 80% unit, also historically common) would be seen in such a closet install.

David, I'm pretty familiar with mini-splits. I've had short term rentals of homes in warm areas with them. One of my kids lives abroad in a warm area and the home has mini splits (which I had to help them understand how to use). My heat strip comment of course related to a standard split system using existing ducts.

No sane person would put mini-splits into an existing 1800 sq ft house with ducts in place.

As for solar install payback, the numbers don't work as you say for coastal California. You're in the South, where people run AC 12+ hours a day for 6 months of the year. In the Bay Area, except during a heatwave, AC is something someone would normally turn on in the few warm months for an hour or two in the late afternoon or early evening to cool the house down. Later on, windows get opened. If you're in Fresno, or Sacramento, or somewhere inland where heavy AC use drives high power usage, different story.

Around here, solar appeals often to people for environmental/social consciousness reasons, not dollars and sense, and that seems to direct conduct. Those who want to save money go the "leasing" route, where an intermediary pays for the equipment and installation and then guarantees the homeowner a reduced power rate over the life of the agreement. These intermediaries often involve the actual companies in the solar business who have a glut of product unsold and realize they're better off getting some return as no return at all.

I just know that many in California state that the payback is very quick. Obviously rates are all over the map in CA. I believe it is mostly people in Southern CA.

Central NC is not quite as South as you might think. Heating drives our heat pump sizing and heat typically costs significantly more than A/C on an annual basis (2-3X in fact). We A/C from June 1 to Oct 1 almost like clockwork. But tonight is 28 degrees and we don't get over 50 for the next week.

Of course here solar appeals to the same people. But with super low interest rates (not so much lately) it can be a rational financial decision also. My recent install had a utility rebate that helped. Last time around, it had both utility and state rebate. It was $6k net for a 6kw system. This time $18k for a 12kw system so not nearly as good (state rebate went away). We are getting a big increase in electric rates this year to help pay for coal ash cleanup - a problem you are smart enough not to have in CA.

"Heating drives our heat pump sizing and heat typically costs significantly more than A/C on an annual basis (2-3X in fact). "

Do you think your sizing comment is misleading? I do.

A 3 ton AC unit will always put out 36K BTUs of cooling. The heat gain to the outside in summer will only rarely be influenced by more than a 25 degree temp difference except in desert locations.

A 3 ton heat pump will have the same cooling output as a straight AC unit. In winter, when it's 50 degrees outside (70 inside ) let's say it can produce (hypothetically) 36K BTUs of heating. But when it's 30 degrees outside, perhaps only 20K BTUs of heating and there's a 40 degree temp difference producing more heat loss. So if the home has a heat loss of 40K BTUs at 30 degrees outside temp, you'd need a 5 ton heat pump or more and supplemental heat. Most installs have both, upsize and supplemental heat.

Yes, heat pumps are frequently sized for heating and not cooling, because their output diminishes as it gets colder. This has nothing to do with anyone's location, it's how they work. And when it's cold, because output falls, they'll be running 24x7 and also with supplemental heat, often electric strips. More consumption than AC.

Buy yourself a nice gas furnace, save money and stay warm!

We are also in the SFBay area. Our house is all electric — with HP heating/cooling along with HP water heating. Even on the occasional 25 degree nights, the HP is still able to keep us comfortable. With 6kW grid-connected solar, our net yearly electricity usage is negative. In our case, the payback time for the solar is only about 6 years, since I pulled the solar permit and did the install myself. I should also mention that our house is a relatively new build, so the insulation is likely much better than most older houses. This makes a big difference in heat losses in wintertime.

Just to clarify, a heat pump can usually hit its labeled output down to the teens, not your suggestion that it can only do 55% of labeled at 30 degrees. That would be terrible and just isn't true.

My manual J had a higher heat loss at out winter design temp of 17 degrees than its heat gain at our summer design of 95. That would be true regardless of heating fuel. It was actually pretty close and our house on the NC coast was sized based on cooling because it has larger windows and warmer winter.

I have had NG and heatpump and there really isn't a difference in a modern system in comfort - at least in our moderate climate. In my latest build, I was partly chasing an incentive. The electric company paid us .90 for an avoided annual KWH - our house is tight so the savings is pretty good. If we use NG as heat, that incentive wouldn't be there.

Also - I had an energy monitor on our last heat pump house and the only time electric strips went on was large manual thermostat changes and defrost cycles.

So - nothing wrong with using NG to heat but nothing wrong with using heat pumps either. And for the most part, using a heat pump is more environmentally friendly.

Wow, your electric rates are almost double mine ($0.1145) but my climate in Sacramento is more extreme vs Sunnyvale. My bill for the heat pump is under $140 nine months of the year and 160-190 the other three (one winter, two summer) for 1850sf built in 1957 with a 450 sf enclosed patio of single pane glass. LEDs everywhere & gas water heater. I didn't use the electric strips in the last two years.

While we do have a PUC, we also have a utility friendly legislature that gave PG&E a pass on the last few disasters and allowed them to pass on the costs, likely with that mandated profit on top. In addition, there is excess capacity in CA, so we also pay in the rates, the cost of capitalizing the unused capacity plus profit my guess is.

If you have a local publicly owned utility, as we do, often they use the large headroom between cost and PG&E rates to determine local rates, as they aren't governed by the PUC. The excess "profit" is used to fund special programs, solar rebates, etc.

The net effect is CA rates are higher than surrounding states resulting in quicker solar paybacks, but also allows solar install companies to make money.

@DMD would love to get details on the solar install.

Springtime, I think what you've said is misleading. To do so intentionally is sometimes called FUD (fear, uncertainty, doubt), it's a marketing/sales tactic to scare and mislead.

Let's talk numbers:

Some heat pumps are described (as you said) as being 300% efficient (though some are at lower numbers). But this is to compare them only to electrical resistance heating. The efficiency stat is NOT APPLICABLE or meaningful as an apples to apples comparison to gas heating, as far as I know.

BTUs:

1 therm of gas from PG+E at the prevailing rate (which applies beyond heating water and just a little more) is $1.76. 1 therm= 100,000 BTUs. With a 90% efficient gas furnace, that $1.76 therm produces 90,000 BTUs of output

1 kwh of electrical resistance heating produces 3500 BTUs. To get 90K BTUs would be 90/3.5 = 26 kwh. At 28 cents (and there is a higher rate too), that would cost $7.28.

Using a heat pump that's 300% efficient (compared to resistance heat) would cost 1/3 of the amount, or $2.42.

So to get 90,000 BTUs from a heat pump is $2.42 compared to $1.76 with gas, more than 40% more expensive. With a 95% efficiency furnace, the cost disadvantage of a heat pump is greater.

Are my numbers or comparisons wrong or misleading?

PS - Efficiency First California is a trade organization that promotes the interests of its members. Doing so is legal but Its site and information from them are promotional in nature for the benefit of its members, it's not objective or independent. As the old saying goes, one needs to consider the source of information to weigh its validity.

Elmer

Your numbers look right and that is why most in CA use NG.

But the point is that solar changes that dynamic because the long term real cost of electricity is not 28 cents a kwh.

I would argue that you are misusing FUD. The FUD comes from people worried about new technology so they sow doubt in people's minds. There is no doubt that NG furnaces in CA heat the majority of homes. There can't be FUD about that.

There can be FUD about minisplits and solar because they are new and still not the "normal".

Now I suppose you can call it FUD to talk about the dangers of NG but generally the term is not used for that. I always thought it was fun that "FUD" is in your screen name.

There is no environmental argument against using solar and minisplits. There is a signficant one about using NG.

Efficiencyfirst - a trade organization but not one for the minisplit or solar manufacturers. So there is that....

Elmer, your comparison ignores distribution and electrical usage of the NG furnace. Perhaps it's not fair to compare mini-splits to whole house distribution but your math seems off.

Using the heating cost comparison calculator from efficiency Maine with the utility prices and efficiency % of your last post, an average home yearly cost with mini-split is $2131 while an Energy Star rated NG furnace is $2021. The extra $100 would easily be recouped in eliminating the monthly, gas fee possible with an all electric home.

For most of the country, the home with mini-splits would be much cheaper to operate than NG.

David,

" the long term real cost of electricity is not 28 cents a kwh. "

I agree. It's going up here and everywhere else, and here substantially so. That makes heat pumps of either type increasingly too expensive to consider when gas is available. Here prices are rising because of the California law mandating a switch in stair-steps to ever increasing percentages of power from renewable sources, which initially are cost uncompetitive with gas-produced electricity.

Heating a home isn't a technology proposition, it's a cost proposition. Even in our mild climate. If the system is operated with a thermostat, and all can be accessed remotely, most people don't care what mechanism is producing the heat. They care about the cost to acquire and operate. Minisplits are more expensive than conventional systems, solar installs are expensive, and the cost recovery for either or both is in the very long term if at all. The rising prices will certainly push home solar installs to become more common, in some areas more than others.

In this area, no matter if it's with or without a home solar installation, minisplits and standard split heat pump systems are much more expensive to acquire and much more expensive to operate than conventional AC and gas furnaces. And aside from the ductless variety (which I'm very familiar with), the standard wall or ceiling mounted units are aesthetically unpleasing and unfamiliar in the US. For now.

Edit to add:

I think you've mentioned "dangers of natural gas" in prior comments. That's a classical FUD, scare tactic approach. You know as well as I do that a properly installed (in a code compliant setting) and maintained gas heater offers little or no danger. Call it no danger.

Springtime,

" distribution and electrical usage of the NG furnace. "

Any system that warms air has a fan to blow out air. Newer ECM motors for conventional, split air/gas furnace systems operate at around 400 watts or less. It's not a substantial cost.

I don't know what you mean by "distribution".

" Perhaps it's not fair to compare mini-splits to whole house distribution but your math seems off"

Tell me what's off.

" For most of the country, the home with mini-splits would be much cheaper to operate than NG. "

The thread began as a question from someone with an existing house in Sunnyvale, CA, with existing ducts, who's looking to put in new systems. It has nothing to do with the rest of the country. I've shown that in this area, heat pumps are more expensive to operate for heating than gas furnaces. And the equipment is considerably more expensive to buy.

You previously mentioned gas supply line installation. That's already there. He's looking for new equipment for what's already there and in place. Using and upgrading that will save him a lot of money compared to paying for all the new connections and work that would be required for a minisplit retrofit

What I meant is that 28 cents is way too high. Using real cost of dollars with time value of money, levelized residential solar is about 8-11 cents.

https://www.solar-estimate.org/news/2018-03-08-how-are-solar-panels-changing-america

You can't ignore that 400 watts that a NG furnace uses. And I would not say that is average. If it runs 5 hours a day that is $16 a month. The minisplit usage includes the blower motor.

Distribution is the duct losses. We ignored this because it is hard to say. The largest study in California that I know of had 30% lost heat to duct work. This would make a NG furnace 30% less cost effective than minisplits - all other things being equal. Since we have no idea of the OPs ductwork, it was ignored. This link quotes that up to 50% of heat is lost in ductwork with the usual being about 30%.

https://www.achrnews.com/articles/124595-doe-leaky-ducts-are-top-energy-waster

The OP said install cost was the same and he was comparing mini-splits to NG ducted. In a typical a/c environment, cost is the same. So - sure ignore gas line costs. For the OP and for most, the cost is pretty neutral.

You gave a 40% advantage to the NG setup. You ignored the blower motor and the average 30% duct losses. It is really close to a wash. Then you ignore that solar costs significantly less than 28 cents a kwh in most situations. Companies exist that lease the equipment to you for no money down and then you pay less than 28 cents. And they make a profit. Help explain that to me.

I get it - you like NG. The green building community disagrees. Solar and wind will never make NG.

" I get it - you like NG. "

Not as much as I like straight answers with no hyperbole.

You're prescribing a heart transplant for someone with a toothache. It's not a new house, it's an existing one. It has existing ductwork. It's not in North Carolina. Our electric rates are going up, there has been publicity about that. Independent HERS testing is required for new equipment installs in California (you wouldn't know that in N. Carolina) so problem areas for efficiency gains and a check of the work done will be identified.

Heat pumps are significantly more expensive to operate to produce heat at our relative rates. That's undeniable. If they weren't, people would have them.

Solar units on roofs? Not yet ready for prime time. Many don't want to have to spend thousands when the savings is tens or hundreds. Too far distant a payback. Remember our real estate is very expensive here - few have extra money to spend after a purchase. The lease approach - I know some people that have done that. The savings isn't that great and, again, it's viewed as a potential negative when the house is sold because the contract would remain for a new buyer. I don't believe there's any guarantee that the built in cost escalation schedule costs would be cheaper than regular retail in the future.

The heat pump costs I presented are for heat production only. Both systems will have blowers. Keep pushing minisplits if you want. You're not ahead of your time, you're pushing something the market isn't yet buying.

I'm sorry, maybe your thoughts play well where you're located. I think you're not very well informed about our local situation and your suggestions missed several key points for this guy in Sunnyvale. Keep pontificating, I'm done.

Elmer, in your example you say a heat pump is 40% more expensive in energy costs than NG. The calculator I linked to includes distribution resulting in ~5% difference.

Distribution for the NG Furnace is assumed to be 70% for the extra blower energy and duct losses, even with Energy Star equipment. An existing duct system could have higher losses and as Jeffrey Grenz points out, sometimes supply lines need to be updated, a questionable thing to do with the direction of the energy grid.

NG combustion exhaust from gas appliances, even those installed to code, can backdraft at pressures higher than 50 pascals. This happens regularly with vent hoods over 400 CFM. Exhaust is an obvious pollution source and introducing it inside our homes is no longer necessary now that electric appliances can be cost competitive and cheaper than gas.

Springtime, you like to scaremonger too. Dispute my heat production numbers with facts or drop your argument.

Yes, old ducts leak. That's a problem everyone should address in older houses and remedy, a little effort goes a long way.

Gas burning equipment (furnaces and water heaters) should be isolated from the interior living space. In my area, these items are in ventilated garages, fully vented attics or crawlspaces or closets/rooms within the structure with floor and ceiling outside air access and tightly sealed doors with weatherstripping. There's no way an exhaust fan creates negative pressure to where these items are located. Address this as fact - how could backdrafting occur? Citing air flow rates and units of pressure may impress (or scare) some but as with the cost of operating heat pumps, you're ignoring facts. Hold the platitudes for the naive listener

Done.

Building codes require make-up air for homes with vent hoods over 400CFM. What some call fearmongering is a life-safety issue. The only reason this code exists is because of inside combustion appliances and the locations you describe are well known to have air communicate with the home. Buildings and rooms under negative pressure risk backdrafting combustion exhaust.

The nice thing about the heating cost calculator link is that anyone can type in their utility rates to check operating costs. Using your numbers yielded a 5% difference. Using the US average of .13 cents per kwh and $1 per therm, heat pumps are cheaper to heat with than NG.

I was done with this thread until I saw that you're continuing to repeat misinformation. Were you ever in politics? You dance around facts pretty adeptly.

Show how my numbers were wrong or accept your mistake as every other reader of this thread will clearly see.

A house in the Bay Area doesn't have US average 13 cent electricity. And in other parts of the state, it's even more expensive. You can keep munging the words all you want but saying it over and over again won't improve the veracity of what you're saying. Your suggestion isn't a good one, gas heat is significantly cheaper here.

Have a nice day.

Your numbers were wrong because you ignored distribution which is a significant thing. They are also wrong because solar is a lot cheaper than you think (but obviously irrelevant if it isn't an option)

Up thread someone from the Bay area posted their solar experience which was a 6 year payback. A real world local example that showed how wrong you are that solar is not practical.

Gas heat is cheaper by a tiny amount when compared to a minisplit in your area. It is not that much cheaper for gas in the bay area - compared to a modern minisplit.

So we disagree.

What misinformation is Springtime repeating?. Please clarify.

I've shown what I think backs up my view with real numbers and real prices, not hyperbole or innuendo. Both of you have responded with BS.

Point out my math error using those numbers or if applicable, corrected ones. This is math, not opinion. If you can't dispute or correct my numbers, maybe it would be better for you to reconsider and re-quantify your advice for this fellow who's in the SF Bay area with expensive electricity, not in North Carolina with cheap power.

Back to this fellow. He has a/c. How much better is a minisplit than an attic based a/c? 30% is probably conservative but it would depend greatly on sun exposure and ... leakiness/insulation value of ducts. Typical would be 50%.

You say BS. Please clarify what is BS?

You use an heating fuel cost calculator that ignores distribution - that is your error. You claim that a heatpump doesn't deliver its rated heat output at 30 degrees. I just looked at a chart that listed actual outputs and they mostly delivered rated output to 17 degrees. They mostly have guaranteed outputs (though less than rated) down to -15 degrees F. So nothing anyone in the Bay area needs to worry about.

This insinuation that I am ignoring CA electric rates is patently untrue. If OP was in NC, the balance would be in minisplit favor - buy a huge amount. In CA, heating is pretty close. A/C is not. The balance point would be how much a/c he needs to use. Might be 10% of heating in which case, it is a wash. And then he might choose to do the better environmental choice.

This has been an interesting discussion

I'm in the same boat.....only in Vallejo. An extremely mild climate comparatively.

To help others keep this simple as far as cost comparisons, a therm of NG = 29.3 kW of electricity.

Using that formula and, the top tier (high usage surcharge) electric rate I pay to PG&E this summer - ($0.38340/kWh) - compared to the Tier 2 gas rate - ($2.02457/therm) - I paid to PG&E at peak pricing last winter, I come up with electrical rate of $11.23/therm eqivalent!

Outrageous. And, completely political.

Now, needing TWO new split HVAC systems for my home plus a new water heater, I ventured into the realm of replacing my existing NG HVACs and water heater with electric heat pump units and having my huge, south facing roof lined with solar panels to provide for all of my electrical needs. And, the crawl space ducting replaced as well, due to rodent damage.

The local Trane dealer was just here and quoted me.........get this, "only" $93,000 to do this.

10kW solar sys- $36,750

HVAC 1 - $15,900

HVAC 2 - $17,500

r&r ducts - $14,400

HP water heater - $ 5,800

upgrade elec

serv panel - $ 2,800

Subtotal $93,150

Less: Tax & Incentives -$33,509

TOTAL COST $59,641

Of course, that would be offset with $33,000 worth of income tax credits and state incentives, bringing the price down to a mere, $60,000! (He overestimated the fed income tax credit or else he thinks I'm a tax cheat)

The problem with all the tax credits and incentives is the same as always It incentivizes the manufacturers and dealers to go wild with their charges and suck them all up. It isn't really a discount incentive for the taxpayer/homeowner.

Yeah, I know his quote is highly inflated, I've compared it to others. And, right now any kind of home contract work in the SF Bay Area is off the charts due to demand being way beyond supply and no tech labor to be found - they all went to the burned out areas in Sonoma County to feast on the offerings there.

But, I really can't see those heat pumps in my case. Electricity is just too darn expensive and offsetting it with a solar system of this size just makes it way worse. It might bolster my enviro cred but it would also rob my children of their inheritance.

I have two more quotes coming in the next month and I'm going to try and stay away from the heat pump option on the HVACs and water heater and see what that buys me.

DMD - It would be of great value if you could provide some more details. You are talking about the system design I was considering and you seem to be saying that 6kW of solar is enough to meet all your energy needs. And, you're in PG&E service area subject to net metering and the same rates I have. That is intriguing. Details please? Details? HP size? House size? Water heater size? Any other large electrical demand items like an EV?

Please? :-)

Just curious, if you fund that $60k at 2.5% interest over 15 years - pessimistic life span of the heat pumps - how does it pencil out? And you probably could do 30 years and put $10k in for heat pump repairs.

Say you pay $3k for utilities a year and go to zero - it doesn't. But if you are at $5k a year - maybe it does.

As you word "offsetting" with solar makes it worse - that is just untrue. Your $20k net system (after taxes) generates something like $5k a year and is warranted for 30 years..

Let me do some math. I have a 11 kw system that cost me about $18k net. This is west facing so if yours is south it generates the same. I live at the same latitude but I won't try to guess on sun exposure but either way we are pretty close. I generated 13 MWH last year which at your peak rates would be $5,000 per year or about a 4 year payback.

I absolutely realize that that 38 cents is your high tier and solar would offset low tier also but you can't go around using high tier only for any of these calculations.

You can call CA rates political - or you can call them environmental. The fact is high rates discourage use and get people trying to minimize. They also make solar a no brainer for most. We probably have to pay higher rates for all this in the rest of the US if we give a crap about the planet.

Low interest rates + high electricity costs = solar for anyone with good sun exposure and access to capital.

I hesitate to comment because I don't think old threads should be bumped but the math here is quite simple.

I live in the Bay Area. Not in Vallejo like Tom but at the southern end. My prices are the same as his, our utilities are expensive compared to other parts of the state and the country. On my last gas bill, gas at Tier 1 was $1.50 per therm and $2.00 or so at Tier 2. In the wintertime, my Tier 1 allowance is just under 2 therms per day.

My house is over 30 years old and 4500 square feet. Our heating season is short and it doesn't get very cold. I couldn't possibly spend $1500/year for heating. It's usually quite a bit less. I bought two new furnaces a few years ago, I think they were $2500 each. My contractor advised me against even getting higher efficiency units. Why? Not enough usage, unlikely payback when considering the need to pay more for the hardware and the install retrofits to accommodate condensate drainage.

Second to resistance heat, which is never seen anymore, standard split system heat pumps are the most expensive source of heat in this area, no matter how you supply the electricity for them. It's the wrong choice. I'm in Silicon Valley and there are a lot of people with a lot of money. For some, it's the technology that matters, not the cost. They think nothing of having needlessly expensive equipment and uneconomically excessive solar panels (to make sure they can say they have no net grid consumption). Most people aren't like that and for them, even with our high gas prices, gas furnaces are the least expensive way to heat.

Elmer J Fudd:

It didn't seem appropriate to start a new thread. And, I really wanted to hear from DMD if possible because I can't make sense of it without details and, Sunnyvale is quite similar to Vallejo climate wise.

Thank you so much for your detailed reply.

The last time I had an HVAC replaced it was in a smaller, older home in Antioch. And, more than ten years ago. The ductwork was the same flex but had no issues.

I went with Trane due to ratings and a few other reasons. I knew I was paying top dollar.

I opted for "only" the 80% efficient gas furnace/air handler for the same reasons you mention about heat vs cooling loads. And, I had a pellet stove insert in my fireplace that we used as much for esthetics as for heating. I did opt for a two speed furnace though because I wanted the ECM motor so I could run the blower fan when the pellet stove was on, only using 100 watts. For the A/C, I upgraded slightly to a 14 SEER unit. The summer heat load in Antioch is a lot more demanding. Those, my decision.

The whole blooming job cost me around $7,000! I knew it was more expensive today. But, not twice as expensive.

I've watched the developments in HVAC and solar over the years out of interest. But, I had little idea of cost. So, when one of my 30 year old A/C compressors went out a few weeks back, I through caution to the wind and let the firm that did the "too old to fix" on site diagnosis propose a serious, net zero type system for me. Like I said, I just wasn't ready for that estimate.

I was factoring, based on neighbor's experience and what research I had done about $50,000 total for the complete system I thought I might want: $10,000 each for the two HVACs, $20,000 for a 5kW solar system and another $10,000 based on what my neighbor paid a few years back, for the ductwork. I only threw the HP water heater in because it's 30 years old, it's oversized, it's on the same "bench" as the two air handlers in the garage right next to them, and I can buy a Rheem HP water heater for $1,500 at HD today. I figured the contractor would install it for less than $1,000 and I can get $1,000 rebate on that but, only if it's installed by a contractor in the BayRen program.

The electrical panel upgrade isn't really necessary. Just a "nice to have option."

Hey, thanks again for the reply.

Elmer J Fudd:

One of my reasons for moving away from NG was because, as you know, the State of California has elimination of it in mind. And, has taken action. San Mateo and Santa Clara Counties have banned it in new construction going forward. So has Berkeley and other such "enlightened" cities.

Yes, it will take years to get to a full ban. But one only needs to look at similar environmental regs and their history to see how fast this actually happens.

The SMOG check program for our vehicles. Developed, expanded and never ended despite the auto industry achievements in emissions reductions of the last thirty years.

The solid fuel bans. It started with woodstoves, expanded to pellet stoves in less than ten years. And now they've started on NG fired heating inserts as those have replaced the solid wood burners from before.

I see NG as being phased out here by pricing and limitation. I know that such noise has been made for the whole nation during this election campaign. CA has already adopted this mantra.

Personal preference, I'd never replace a gas water heater with an electric one. Cost of operation and recycle time are inferior to what gas heaters can do .

Never say never....

Wouldn't long term solar be possibly cheaper than $2 a therm with a heat pump hot water heater? And if the tank is big enough, why do recycle times matter?

Sounds like personal solar (in CA with incentives) would come to about 10 cents a kwh with 15 year timeline and that would be cheaper than $2 a therm with a 2.5 COP hot water heater.

I mean you can't call electricity 30 cents or 38 if you get solar.

And that is what you are doing when you say that heat pumps are more expensive than NG - you are using 30 cents.

Doesn't necessarily make it wise to rip out NG furnaces or water heaters but it doesn't make electric units (HP) uneconomic either.

Check out the COP ( the Coeeficienat of Productivity) of Heat Pumps vs regular AC or gas/or electric heat. HP will outperform every time. Cost may be more to install but that will come back as a return on investment. And you're helping the planet by using less electricity and producing less carbon (in the fuel your te utility burns).

Also, you can zone each device separately so you have a lot of control. You should also consider indoor air quality and work in some mechanical ventilation ( ERV and scrub out the heat/or A/C entering or leaving)

"Check out the COP ( the Coeeficienat of Productivity) of Heat Pumps vs regular AC or gas/or electric heat."

As has been discussed in this forum many times, and as I suspect you probably know, "efficiency" numbers for electricity-generated heat, whether by resistance or heat pump, live in a completely different world and express something quite different from efficiency numbers for gas fueled appliances. They refer to two completely different concepts and are unrelated and not comparable, are not meant to be lined up and assessed across the different platforms, and speak about completely different things. I hope you don't try to munge truth by attempting to compare them that way.

I like our heat pump water heater. For our family, the longer water heating recycle time compared to gas or electric has never caused us to be out of hot water when needed.

We also have a heat pump for heating and cooling. It’s great in our SF Bay Area weather.

For our all-electric home with grid-connected solar, our yearly electricity expense is negative.

Hey Tom,

Some details: My house is 2300sf single story — a new build (2013) with 2x6 walls and good insulation. HP is a 3 ton unit. HP water heater is a Geospring 50 gallon. No EV loads (yet!). Biggest electric loads are a clothes dryer and 3/4hp well pump.

If I ever need more solar generating capacity, I will go pull a permit and buy and install myself. Really cuts the cost WAY down.

PG&E provides distribution, but I get power thru Silicon Valley Clean Energy. They have a net energy program that pays cash for net excess energy generated at the end of each year. So, in addition to paying only about $11/mo for distribution (more than offset by the twice yearly climate credits), I get a check for about $200 at the end of each year.

DMD

Thank you for the response!

What you have makes a lot of sense both economically and environmentally. Part of that is the "new build" factor. If I were to build today, I'd incorporate all of what's been discussed here and a lot more. But, when it comes to retrofitting these products, cost/benefit deteriorates quickly. At least at the cost contractors want these days.

The fact that you heat and cool 2300 sq ft with a 3 ton HP unit says much about the insulation and air tightness of your home in the first place. I'm in a situation - no accessible attic - where adding insulation to the ceilings is especially convoluted and expensive.

I saw the 50 gallon Rheem hybrid HP water heater on sale at HD just a few weeks back for just over $1,000. But, when I suggested to the A/C contractor that we have them pick one up and install it at the same time they do the A/C system, they wanted $5,800! Another, reputable energy auditor told me that they can't make any money installing HP water heaters for $6,000 and that they've lost money on an $8,000 install for an HP water heater.

Something ain't right!

I'm a serious DIY person and have even helped friends build their own house. I too would like to do a self install on solar PV and will certainly be doing so for an HP water heater if I go that route. But, I'm getting up there in years and not able to hop around on a roof like I once did. Plus, all my DIY friends have moved out of state and I don't have anyone to help me for jobs that require more than one person. So, I'm heading down the "call the guy" path and just finding the whole process frustrating and ridiculously expensive. Most of the time, these well rated contractors won't even call me back to set an appointment. My neighbors have been experiencing the same thing.

DMD,

Your mentioning having a well pump suggests you're in a low density location. That's fine, no problem.

Home water wells are uncommon in the Bay Area and that's typical of the more remote parts of the region. Such areas often do not have natural gas service. Does your home have natural gas service available?

Hi Elmer J Fudd,

No NG service here - just outside of San Jose. We had the choice between propane (very commonly used in my area) and electric. Propane is roughly 4x the cost of NG for the same amount of energy. Going with all electric was the best financial choice for us. Of course a number of things are in our favor: new energy efficient construction, owner-builder install, availability of tax credit, utility rebate on HP water heater, favorable net metering program,... Obviously being able to source all equipment/materials and doing the install myself saved a huge amount of $. No mater the particular situation, being able to do an owner-builder install changes the financial analysis considerably.

It still amazes me that with a 6kw solar system, we can bring our total yearly utility costs negative. This is what I believe Tom was interested in hearing about.

"No NG service here"

I suspected so. Whether it did consciously or not, I have to believe that greatly influenced your decision. With or without solar panels, you really had no other choice but to heat by heat pump.

"Obviously being able to source all equipment/materials and doing the install myself saved a huge amount of $."

I think that's great that it was something you could do yourself. I think you understand that it's something few people would be inclined to do themselves, so that your financial experience is instructive to only that very small group of people with the time and inclination you had.

Hi ElmerJ Fudd,

”Whether it did consciously or not, I have to believe that greatly influenced your decision.”

Of course it was a conscious decision. I don’t understand your point here.

There are multiple discussions and points being argued on this thread. I am not taking part in all of that and am simply answering Tom’s question asking for details about how I’m able to run my all-electric house with a 6kw solar system.

And finally, I’m happy if my experience can help even one person.

My point is that your "advice" concerning what you did is less relevant to folks with natural gas service than to those without it. The vast majority of people living in the Bay Area have natural gas service and most choose that energy source for space and water heating.

Having that fact in hand helps to explain your choice. There really wasn't one.

Hi Elmer J Fudd,

I don’t think I am providing “advice” — simply responding to specific questions and comments with my own experience, and nothing to do with NG being available or not. I will leave it to “experts” to provide proper ”advice”.

Other than that, of course what you say is obvious and true.

DMD - you also made this calculation in 2013. Hard to know exact street level net pricing in one region but averages for solar are down about 25% since then.

National averages in 2013 were about $4 a kwh and are now below $3 even in CA.

Arguably, NG is down a similar amount in the same time period but I don't think CA rate payers feel that.

If you're negative in grid usage, DMD, some would say you've got too much capacity installed.

The greatest payoff of course is to offset usage in the higher priced tiers. Tier 1 usage, though still expensive compared to other areas, much less so.

I had new neighbors move in across the street last year who had solar panels installed on their street facing, south facing roof facet. No problem, I think most people accept that the appearance of panels is the new normal and has a beauty of its own.

Anyway, this couple is in their mid-late 70s. The house has no AC and has a gas furnace (I know because we were good friends with the former owners). The new owners are both recent cancer survivors. Their children do not live in the area. In talking with them at the time, the guy said "we're really excited about our new solar system. The return on investment is terrific, we should recoup our initial out of pocket costs in 10 years". I could only think with that, that the likelihood of either or both of them being around in 10 years and still living in their two story house is very low. But that's common among a surprising percentage of people who install solar - their enthusiasm is only an echo of what the salesmen told them, they themselves have little understanding of what they got into. I'm not suggesting that to be the case for you, DMD, not at all.

I support solar, I know it's the future. I'd like to see a lot more of it installed and more subsidy programs in place to encourage it. A remaining issue in a broader sense is to resolve how to address grid base supply when it's dark. But sliced bread and canned beer are still the greatest thing going, solar power isn't there yet.

H Elmer J Fudd,

I see what your saying. I think everyone considering a solar install should go thru all these considerations and carefully calculate if it works for them.

As for me, I plan on being at my current location for at least 40 more years. And I’m fortunate to have an energy provider that pays me a non-discounted rate for all excess energy I produce. I’m sure not everyone has access to that kind of deal. If interested you can check out the details at: https://www.svcleanenergy.org/solar/

So for my situation, going with solar was a very easy decision from a financial perspective.

Also, I’d love to add batteries and go completely off grid, but that definitely doesn’t work from a $ perspective at this time.

An interesting note is that after the SCU complex fire went thru our place, we were without power for about 2 weeks. With careful choice of which higher current appliances were operating at the same time, we managed just fine with an 8000w generator. I was thankful for that.

Hi Elmer

I read through your comments strongly supporting NG over HP option due to its cost advantage.

Do you know a 10 KW solar system can be installed in CA today for $15000 after tax incentive , which will generate approx. 15000 KwH of electricity per year ? I am exactly doing this for my 1995 built 3375 sq ft home in bay area as this appears to be the cheapest route to bring down my energy cost as compared to other options like improve insulation, change windows or upgrade 1995 installed 80% efficient NG furnace etc.

Till my NG furnace is alive and kicking, I plan to use it minimally in the morning to take the chill out of the home and rely on supplemental electrical heating ( resistive ) to keep the house warm . Resistive heating is inefficient, but ok as stop gap option particularly if my electricity is coming from solar.

When it's time to bid farewell to these antique NG fired machines, I plan to take HP route for my home heating and air conditioning.

Even without any of these actions and just install of solar, my current electricity only bill will be reduced from $2800 / year ( 10000 KwH ) to zero. That will pay for solar install cost in just 5 years. Add to it cost saving from an electric car ( which I don't have at this time ), payback is even shorter.

My yearly NG heating consumption is 700-750 therms. The baseline consumption of 20 therms / month or 250 therms / year will always remain due to NG cooking appliance and NG water heater. But the rest 500 therms / year NG consumption can be eliminated when I replace central ducted existing NG Furnace / AC system with ducted heat pump (no splits). There will be more upfront cost to install heat pump as compared to NG furnace / AC option , but I am hoping this differential to be in the range of $2-3K , particularly if I go with heat pump option like MrCool Universal ( will work well in temperate Bay Area weather ) instead of fancy Fujitsu or Mitsubishi heat pumps. And saving of $1000 from eliminating consumption of 500 therms / year should help offset this cost sooner rather than later.

Due to these considerations, I decided to go for 10KW Solar System that gives me enough capacity of solar generated electricity to meet these loads.

Time to give a fresh look to all ( almost ) electric home with recent price reduction ( actually since June, 2020 ) in solar install cost.

Where do you get 10 KW system for $20k pre-incentive? I recently install LG panels and it's 5 KW for $20k in San Jose. My friend got $18k for 8 KW with Tesla crazy pricing.

Hello Trong

Sorry I saw your question just today.

If this late reply helps, I bought my 10 KW solar system from Tesla for $19500 pre-incentive in Nov, 2020. It was a well advertised no haggle price on their website.

Even today , it is available to order for $22K approx I guess.