0
Your shopping cart is empty.
gahockey45

Is a heat pump right for us? New Construction

Remington
February 6, 2019

Location: Northeast Ohio

- Humid summers (temps can be in the 90s)

- Cold winters (temps can be in the single digits or below zero like we recently had)


We are planning to build a home on a lot we recently purchased. It is in a rural location, so natural gas is not available. Other homes on the street have propane cylinders above ground, so we are leaning towards a propane fueled furnace and AC unit.


We feel this set up will lead to expensive operating costs. Propane is around $2.50 per gallon in our area. We would have a 500 gallon above ground propane tank.


I asked my builder to quote a dual fuel heat pump with back up furnace system. He told me approximately $5,000 for a Trane 18 seer unit. I don't know the model number of the unit, but I requested the quote to reflect a heat pump unit that can operate at lower temps.


The home will be a ranch style with full basement and bonus room above garage (1.5 story)


I have the crazy idea of a wood burning stove installed in the central area of the home, but my wife is not thrilled with that idea. Geothermal is not an option (not in our budget with such a high up front cost).


Is a heat pump the right option for us? What would you do in our situation?

Comments (75)

  • Elmer J Fudd

    " If there were "zero risk" as you say, there would be no make-up air requirements for vent hoods over 400 CFM.

    I hope you know more than to conflate every construction technique or requirement into being a mitigation for a life threatening risk. Or maybe you don't? Some are just common sense, codified to prevent dumb or money hungry builders from taking imprudent shortcuts.


    It's a public space, say what you want, but I think you'd have more credibility if you left off the extreme, unsupported comments.

  • ulisdone

    I believe someone mentioned using portable propane heater for power outage backup heating. Now that is dangerous in a modern home.

    Definately install a wood stove for peace of mind, no matter what electrical based system you use for your general heating.

  • PRO
    Virgil Carter Fine Art

    Backup heating sources in the event of a power failure is only one issue among many. There's the food in the refrigerator and freezer. There's preparing food to eat. There's lighting needed to see at night. There's power needed for the well and sump. Telephone, TV, computer, alarm, etc. What else?


    Some areas are prone to frequent power outages. Some are not. For those areas which experience frequent power outages, a backup generator, with one power source or another, and the proper switchover circuitry is not a big deal as long as one plans for critically needed circuits and not the entire house.

  • PRO
    Springtime Builders

    Prefer standby LP or NG generators over portable units that run on gasoline. At least generator exhaust happens outside of the building envelope. Recently spoke with a client for whom we installed standby generator propane infrastructure and he is considering having it removed in favor of batteries integrated into the existing PV system. Happy this once pipe dream is becoming reality.

    My point upthread was high efficiency heat pumps have lower energy costs than propane, half the costs in OP's case. I don't think mentioning how heat pumps carry less health-safety risk than indoor combustion appliances is extreme but agree credibility is improved with sources.



    This illustration from Natural Resources Canada, Combustion Gases in Your Home shows the common mechanical appliances that can suck combustion appliance exhaust into your home. Offenders include dryers, bath fans, whole house vacuums, kitchen vent hoods and not pictured outdoor-air-ventilation exhaust-only fans (mechanical ventilation).

    The most reliable backdrafter is the vent hood. It's why code requires make-up air MUA over 400CFM. This is a code requirement, whether there are combustion appliances installed or not. Presumably, someone could add a combustion appliance later, putting the occupants at risk. The code won't protect the homeowner who later adds a powerful vent hood sans MUA, either through DIY or using a cartoonish contractor who dismisses such fear mongering health-safety issues.

    I agree with 400CFM being a good threshold but it could be argued as arbitrary. Some suggest 300CFM while Dr Joe of BSC suggests providing MUA for all vent hoods, exhaust-only fans and dryers. Code minimum is no panacea. Only by eliminating the source of indoor combustion do you eliminate the risk of backdrafting combustion exhaust.

    Power or direct vented appliances are safer than natural draft appliances but they can still be depressurized at 25-50 Pa of pressure. Our most recent home's tankless gas water heater will not operate with the vent hood running. This is both an inconvenience and red flag that if or when the safety feature fails, the combustion exhaust will backdraft.

    Inspectapedia has a decent Backdrafting Heating Equipment Hazards Guide and good to see that even a gas utility has a small section on the danger of backdrafting. From the OP's home state, the author of Energy Smart Ohio offers this resource on Why Gas Water Heaters Suck.

    Those interested in more scholarly medical resources can check out Causes and Consequences of backdrafting of vented gas appliances from NCBI. The similar articles there offer other rabbit holes to explore. They raise good points that research is lacking and low level exposures are surprisingly common.

    This medical study pointed to in Energy Vanguard's Are We Off Track with Combustion Testing? estimates 40,000 people a year end up in hospitals from CO exposure. John Proctor's comment is especially important. Most CO poisoning cases are from low levels and go undiagnosed. Safe exposure limits may become irrelevant now that electricity is cost competitive and often more affordable, there seems little reason to include the added risks of burning gas inside.

  • simmtalker

    Deleted post where I quoted Virgil. Sorry, never meant any harm by it.

  • PRO
    Virgil Carter Fine Art

    Yes, yes, yes...our forefathers never had electicity or a backup generator. Welcome to the 1800s...


    FWIW, I've lived in an area with frequent power outages, and it was much better having a backup generator.

  • simmtalker

    Virgil, you are jumping to an extreme, which strikes me as unusual for your posts. I am not saying it's not great to have a generator, or that people should not have generators -- heck, it's on my list!!! I am only pointing out there are solutions for each of the things you listed.

  • PRO
    Virgil Carter Fine Art

    Of course there are solutions...there are always solutions. But are the solutions what one really wants to do? Are they the BEST solution? Are they even needed solutions?

  • simmtalker

    Of course there are solutions...there are always solutions. But are the
    solutions what one really wants to do?
    Are they the BEST solution?
    Are they even needed solutions?

    People don't like to clear snow off driveways, even complain when they have snow blowers....guess the better solution is hiring a company to clear it. People don't like to clean, but maid services are available. People don't like to do laundry, but guess they could drive two hours to go to a full service cleaner. I could go on... It takes MONEY to use these solutions, and not everyone is in a place to solve all of life's inconveniences by throwing more money at them.

    I am sorry I quoted your post, really didn't think you would mind. I will delete it.

  • Elmer J Fudd

    "I don't think mentioning how heat pumps carry less health-safety risk "

    I think you live in an area where coal burning power plants have long been standard fare, so this comment really isn't true either. There are far more health risks from coal plants than from your make believe home combustion issue. Heat pumps are more healthy in such locations as yours ONLY if powered by on-site solar so as to not create more demand of the coal plants but the cost of having enough home solar capacity to power a heat pump is uneconomical. Especially so in low cost coal-derived power areas like North Carolina.

    In the meantime, properly installed and maintained gas appliances, as are present in TENS OF MILLIONS of US homes, present no significant risk. Manufacturer and code requirements stipulate the need for outside air. When building a new, uber-tight home in an area of extreme weather, sure, different story. As far as exhaust hoods are concerned, most people I know don't use what they have and the ones who do are thoughtful enough to realize they work better if you crack a window.

  • PRO
    Springtime Builders

    New homes are required to be tight enough to challenge your assumptions. Studies of leaky homes find plenty of risk. All the resources I linked to explain how it's much more complicated than managing risks with cracked windows. Is it smart to pay more, to add risk?

    Coal is bad but so is fracking for gas. When people choose electricity, they are taking part in an increasingly renewable energy picture. No such thing as renewable gas.



  • David Cary

    Coal is 26% of NC energy's generation. It is 30% of US so we are comfortably below average.

    We are second to CA in solar.

    We are 3rd of the 50 states in Nuclear. It is our largest energy source.

    We have the largest windfarm in the Southeast US - came on line in 2017.


    So Coal-derived is probably not an accurate assessment of our electricity generation. 18 states derive more than 50% of electricity from coal. 24 states mine coal. NC is in neither of those groups.


    NG kills people. Coal kills people. All energy sources kill people. My home is pretty tight. I feel safer with a heat pump but honestly there are a lot of bigger things to worry about.


    But a little true story. My make up air damper doesn't work. No inspector caught it. GC and HVAC people didn't catch it. This happened 4 days ago (we moved in 3 weeks ago but the vent wasn't working until about 10 days ago). I was running the vent and decided to open a window. The breeze rushing through that open window was tremendous. So I did some digging and the damper isn't opening. It is also inadequate but good enough for the code inspectors.

  • tigerdunes

    for OP


    fuel cost comparisons


    Cost per 100,000 btu of useable heat


    Electric baseboard: $3.43

    Heat pump: $1.27

    Propane: $1.96


    using your fuel costs, 95% eff for propane furnace, 3.0 COP for fuel pump....

  • mike_home

    Using these fuel cost comparisons, heating with a propane fueled boiler and baseboard heating would cost about 50% more than a forced hot air system and a heat pump.

    On the other hand, if the home was all electric with no propane available, the back up heat using electric heat strips would cost 75% more compare to a propane fueled furnace.

    Tigerdunes, I calculate the electric baseboard cost would be $3.81 at $0.13 per KWh and 100% efficiency. This is using 3,412 BTU per KWh. There is always some loss in the electric wiring which would make the cost even higher.

  • PRO
    Springtime Builders

    High efficiency heat pumps don't necessarily include electric resistance heating strips. The heating cost comparison calculator from my first post is nice because it's easy to use and makes good assumptions.

    Using OP's rates and minisplit heat pump in colder Maine climate, propane furnace is nearly 120% more in energy costs.

  • Elmer J Fudd

    My coal comment was because Springtime Builder's background says he's in or near Asheville, NC. There's a fair sized coal power plant on the outskirts of Asheville so that's the power source for the area.

    So as not to be misunderstood, I understand that heat pumps are a great option where electricity is relatively inexpensive and/or if natural gas isn't available. My comments were motivated by this person whose attitude seems to derive from an assumption that the people he's speaking to are know-nothing morons and so scurrilous comments will be accepted without further thought.

  • weedmeister

    I would probably recommend a duel fuel system of high efficiency heat pump with propane backup. The setting of the changeover point (electric to propane) would depend on the heat pump low temperature performance, how you feel about the heat being produced, and the cost of propane (it can vary over time much more than electricity).

    Since this is new construction, I would also invest in extra insulation. Like R25 walls and R50 or R60 ceilings.

  • mike_home

    "High efficiency heat pumps don't necessarily include electric resistance heating strips."

    That might be true for milder winter temperatures in the south. You will need back heating when temperatures fall below 10 degrees. Also don't forget heat pumps are sized for the cooling load. A house in the north which can be kept cool with 3 tons (36,000 BTUs) of cooling may have a much higher heating load during winter lows temperatures.

  • PRO
    Springtime Builders

    Ductless heat pumps are available with rated capacities (no heat strips) as low as -15F and many are reporting continued operation at -22F. Maybe not full capacity but by leveraging this performance with heat strips, it seems unlikely to be cost effective to add a propane furnace instead. Mitsubishi hyper heat models are rated at 100% capacity at 5F.

    5 degrees is a design temp threshold used by NEEP cold climate heat pump listings and is the coldest design temperature where people might still consider an American made ducted system. Cleveland and Akron are in.

    Building Science Corporation has been doing Long-Term Monitoring of Mini-Split Ductless Heat Pumps in the Northeast and Green Building Advisor has a good article on Ducted Air-Source Heat Pumps from American Manufacturers, though probably behind paywall. One of the ducted Mitsubishi combinations performs at 80% of rated capacity at -13F.

    Design temp sizing is obviously important but the majority of time is more mild and choosing equipment with good turndown ratios can really pay off. For the better part of this average February day, my Mitsubishi ductless was heating with a COP near 4.5.

  • mike_home

    Post the mini split model number that operates down to -15 F degrees. I would like to down load the product data sheet. I am curious to see what the is the heat output.

  • David Cary

    https://www.fujitsu-general.com/us/resources/pdf/support/downloads/halcyon-2018-full-line-brochure-02.pdf


    Question wasn't directed at me but here is the Fujitsu model brochure. They have a large number of models. Some are rated to -5 and some -15. The -15 models are all over the place in regards to % of rated output at -15 but most are above 100%. I did see one as low as 76% so you need to check. Most of the 1-1.5 ton units are 100% or more. I think a 2.5 ton unit was the one down to 76%.


    The 18RXLFWH is 100% while the 24RXLFWH is 82%. Other models are similar - the smaller unit in a series gets full rated while the bigger does not. Unfortunate but hardly a deal breaker as long as you are smart about it. New construction should be easy to set up for the lower sizes with decent insulation.


    In case it isn't obvious the 18 stands for 18,000 BTU or 1.5 ton.


    I suspect that most modern residential construction would find 1.5 tons to be enough for a minisplit unless there were really large windows in a large great room. It kind of makes sense that they engineer for rated output on the smaller systems since that would be what most outside the US would be fine with. You typically see good modern construction below 20 btu/sqft so the smaller mini would cover about 1000 sqft - which is about as much as you would expect from an airflow standpoint. Just for comparison, the Passivehouse standard is 3.2 btu/sqft just as an example of what is possible. At that level, you would only be getting the 9,000 btu models.

  • tigerdunes

    for Mike


    i stand by my calculations includng electric resistance heat. I used Warm Air. Com fuel cost comparison calculator.


    electricity $.13/kWh, propane $1.70 gal


    heat pump eff 3.00 COP, propane furnace 95% eff


    TD


  • tigerdunes

    getting a bit off subject with discussion of coal fired generating plants...for those outside the area, Duke Power was fined for the illegal dumping of coal ash and included the cost of the cleanup and fine in their latest rate request to NC Utilities Commission....not a good corporate or environmental citizen,,,,

  • Bryan Williams

    A few people have mentioned insulation but my opinion is that is key. Spending a little extra on insulation and tighter construction will save money no matter what type of system You install. That being said...


    since natural gas is unavailable I recommend a heat pump. However, I would still install a propane tank to supply gas logs, which will greatly aid the heat pump in extreme cold, and a tankless propane water heater. im Not sure if it is prevalent in your area but spray foam insulation is being widely used in the south. Your insulation contractor can spray foam your duct work to get virtually a 100% sealed duct system. This is basically a wash as far as cost but will greatly increase the efficiency of your HVAC system. Variable speed HVAC systems would Also be a recommendation. This will allow for better humidity control and energy savings in the carrying climate in your area. Dual fuel heat pump would be an option. Don’t be scared of exhaust if you use a reputable contractor. Also you should have your system serviced for each season.


    Hope this helps.

  • mike_home

    Tigerdunes,

    Correct me if I am wrong, but here is my calculation assuming 100% efficiency

    1 KWh = 3,412 BTU

    (100,000 BTU/ 3,412 BTUKWh) * $0.13/KWh = $3.81

    I think this is correct. Maybe warm.com has a mistake in their calculator for electric costs?

  • PRO
    Springtime Builders

    The BTU quibbling over electric resistance vs propane may be useful but ignores the total lifetime costs of the equipment. Ductless heat pumps are very affordable compared to gas furnaces. Electric resistance heating like baseboard or cove types are dirt cheap and could last 50-100 years with zero needed maintenance or replacement. Gas furnaces are expensive to install and maintenance costs alone can easily negate fuel cost savings.

    The extra costs of heat strips for heat pumps are minimal. The extra costs of a gas furnace system and all it's accompanied infrastructure is significant.

    The same rationale can be applied to cheaper Natural Gas NG. Will a system that adds thousands of dollars in upfront costs payback with yearly fuel cost savings? Just the monthly, minimum fees from NG utility can be enough to wipe out differences in fuel cost. Using NG furnace and heat pump average efficiencies, it's close to even or cheaper to heat with electricity for ~15 states without including extra fees and infrastructure of gas.

    Another problem with the dual fuel solution is the communication. When a system switches over to gas, the heat pump stops contributing it's leveraged efficiencies. This is especially problematic for the newer high efficiency heat pumps that have no problem gathering heat out of very cold air. Much easier and more affordable to integrate heat strips.

    Agree that insulation and tight construction play major role. Tight construction more so. Most new homes do not seem to be blower door testing and for those that do, the results are somewhat pathetic. With the current state of the industry, a tighter blower door test is more cost effective than additional insulation concerns over code minimum. Of course many projects seem to fall short of code on insulation too.

    For projects that can accommodate appropriate space, which should be priority for those in design, it's likely cheaper and safer to heat water with a heat pump water heater.

    Bryan Williams also says don't be scared of exhaust with reputable contractors. I'm not so sure. I bet David used reputable contractors yet everyone missed his new, non-functional MUA unit. We use the area's best HVAC subs and take the safety of our clients very seriously. On the project mentioned above with a tankless gas water heater, the MUA unit is installed per code and was commissioned by a HERS rater. Yet the vent hood is still depressurizing the house enough to backdraft the "sealed" combustion water heater, should it's automatic safety cut-off feature fail.

    I somewhat agree with David that there are bigger concerns, namely how most new construction does not seem to be including outdoor-air ventilation provisions that are supposed to be required by code. I would rather live in a house with "sealed" combustion appliances that meets ASHRAE 62.2 or BSC-01 than live in one with zero combustion nor outdoor-air ventilation.

  • Elmer J Fudd

    "Gas furnaces are expensive to install and maintenance costs alone can easily negate fuel cost savings"

    More nonsense.

    "minimum fees from NG utility "

    I don't pay any such fees at either of two homes served by two different gas utilities.

  • PRO
    Springtime Builders

    Not sure how much gas furnace installation is in CA, but for most of the county its at least a couple thousand $. Maybe furnaces don't break down in CA, but according to this site repairs averaged $160-268.

    Most of CA is served by PG&E which charges minimum $120 per year for most people. That's even if you use zero therms. I've heard minimum fees can be as high as $25 per month from some utilities but would guess the average is closer to PG&E's.

    Those extra costs are for existing homes with gas infrastructure already in place. New construction needs to include the gas supply line with associated trenching, appliance drop charges and venting infrastructure. Drop charges and venting should be included in HVAC contract but not necessarily the supply from the street which can include trenching, backfill and related disturbance. In our area, the gas company insists on coming in towards end of the project ensuring plenty of messy rework.

  • Elmer J Fudd

    Thank you for showing how many people get wrong information from internet searches and don't know what they're looking at. I can only share my experiences and information I know to be reasonably accurate

    Maintenance and repairs? Four years ago, I replaced a 30 and also a 20 year old furnace that had had no repair needs. I know because I had them installed. The last few years, I'd had inspections every 2-3 years (about $100 combined cost). When the best regarded (and not the cheapest) contractor in town replaced them, in response to my question about the frequency of maintenance, I was told "if you replace your filters regularly, as long as they seem to be working okay, there's no need to call us".

    I bought a second home about a year ago. It has a 21 year old furnace. I asked the seller about repairs or maintenance done and they said "No, it works fine". And it does. I'm going to be replacing it soon for another reason but another instance of no repair or maintenance needs.

    "That's even if you use zero therms. I've heard minimum fees can be as high as $25 per month from some utilities but would guess the average is closer to PG&E's."

    Boy, you missed this one by a mile. The PG+E web page you link to concerns electricity, not gas. It says there's a minimum monthly BILL of $10 if little or no electricity is used. $10 equates to about 45 kwh in one month of usage. For customers using more, there's no such charge, the electricity bill is based on consumption only, no monthly or other service charges. Gas is the same. I get monthly bills from them, you can argue all you want but your information is wrong. The correct number is $0. Tell again what you've heard about PG+E?

    Most of California is served by PG+E? Well, not really. Its territory is roughly from Bakersfield north to Oregon. A big plot of ground, but with cut-out exceptions for other systems, including municipal ones. AND, most importantly, this area doesn't have anywhere near half of California's population. Maybe more like 1/3?

  • PRO
    Springtime Builders

    Woops definitely messed up the PG and E link. According to this page PG&E, which is the biggest utility provider in CA (and the nation) charges .098 cents per day so $3 monthly minimum gas fee. Y'all are lucky to be way below the national average minimum of $11.25 according to this American Gas Association analysis. I wouldn't bank long term on that low price with the AGA suggesting $24 as the closer cost for utilities thanks in part to aging, leaking infrastructure.

    This article on why your gas company charges you even when you're not using any gas lists Maine minimum gas fees from $14.29 to $35.00!

    Using the national monthly average of $11.25 and assuming a 25 year furnace lifespan, $3,375 is a lot of money to pay for no gas.

    My experiences with furnaces are much different than yours, perhaps due to your mild climate, which would extend to all heating systems. Furnaces certainly need more attention than some backup electric resistance heating. I don't recommend people ignore combustion appliances and their venting infrastructure for 20 years.

  • Mrs Pete

    We have a heat pump -- most of us Southerners do. We replaced ours 3-4 years ago, and -- yeah -- 5K sounds right. However, we only replaced the heat pump itself; we already had ductwork in place.

    Our heat pump is great for our moderate Carolina temperatures, but on the few days of the year when we get really, really cold temperatures (which, to us, means teens) ... and our heat pump runs non-stop, which isn't good for the machine and costs a fortune.

    I am under the impression -- though I don't claim to be an expert -- that heat pumps are for those of us who live in moderate temperatures, and they're not for people who have cold-cold temperatures for a majority of the winter.

  • PRO
    Springtime Builders

    Mrs Pete, technology has evolved but it's not exactly standard. People with efficient homes are using heat pumps as their main heat source in climates colder than New England. Unfortunately, American manufacturers are playing catch up. What's currently available from the likes of Mitsubishi and Fujitsu are incredibly efficient in both humid summers and cold winters.

  • Elmer J Fudd

    "Woops definitely messed up the PG and E link. According to this page PG&E, which is the biggest utility provider in CA (and the nation) charges .098 cents per day so $3 monthly minimum gas fee. Y'all are lucky to be way below the national average minimum of $11.25 according to this American Gas Association analysis. I wouldn't bank long term on that low price with the AGA suggesting $24 as the closer cost for utilities thanks in part to aging, leaking infrastructure."

    Well, you blew it again. I think you should stop, you have a consistent knack of finding things you don't understand. I would think you would find this to be embarrassing. The gas tariff you cite shows a minimum transportation charge as a per therm component. Here's a bill of mine from last summer, when my therm usage was less than one per day. There's no charge other than for the therms used, a total of 15 therms in a billing period of 31 days. The only charge is for the therms.


    Beyond your false assumption (about a subject you seem to have little knowledge of), please tell me why a house with gas service would have no usage. As my bill shows, two water heaters, a clothes dryer and cooking produces some usage, although at a trivial cost in a high cost area. Your assertion that someone would pay some grand amount for nothing at all is vacuous and uninformed.

    "I don't claim to be an expert"

    Here's something we can agree on and understand why.

  • PRO
    Springtime Builders

    Elmer, you just quoted Mrs Pete, not me. I'm confused what you are disputing. I have provided maybe 20 outside sources in this thread. Feel free to dig deep and provide something other than your feelings. Per day is different than per therm. Did you try to post your bill? Not seeing it.

    Even if PG&E has no minimum, it doesn't change my point. Most people face monthly gas minimums that can have big impact on gas vs electricity.

  • Elmer J Fudd

    She was saying what everyone was thinking about you. My apology and my thanks to Mrs. Pete.

    I just find your persistent misinformation and false assertions puzzling. You spoke about PG+E having a minimum charge and referred to the gas tariff schedule. There is no minimum charge and you misunderstood what your Google search found for you.

  • David Cary

    Just to give another data point, here in PSNC area, we pay $10.70 for zero usage. I suspect CA is a little different since everyone has a number of NG appliances so using zero isn't very common. That is a byproduct of expensive (and tiered) electric rates.

    So you have NG dryers etc.

    Most of the rest of the country probably has charges to pay for the infrastructure. It makes sense and is logical. Doesn't make it so of course.

    For me, I sucked up the cost for a fireplace and cooking. Not the right budget choice but done either way. I suspect that is true for a majority of new home builders when given the choice of no NG or not. I considered a propane tank for that but $10 a month is really not much.

    When there was talk of charging $800 for the line to the house (because I didn't put in a furnace), I did consider propane. In the end, I didn't pay that.


  • PRO
    Springtime Builders

    My apologies, I assumed we were talking single family residences. You appear to be in rate plan G1 T Mobile Home Park Service which is exempt from the per day minimum fee.


    It's commendable that utility commissions are having other ratepayers subsidize lower income housing but I'm afraid an unintended consequence could be higher public health costs by encouraging indoor combustion usage. Smaller spaces are even more vulnerable to backdrafting.


    CA is also known for influencing market forces in favor of NG over electricity. I wonder if PG&E's unusually high minimum monthly fee for electricity and unusually low minimum fee for gas is a way of having electricity ratepayers subsidize gas pricing.


    You mentioned replacing one of your furnaces but you may want to consider minisplit(s). A right sized minisplit with good turndown ratios (very low modulation) is capable of 400% efficiency or better for the majority of time in your climate which should beat NG at your rates. Of course you get extremely efficient AC too, if you need such a thing in that dreamy climate.


    I'm no expert in public utility policy or sizing equipment. Aside from building homes, my education and expertise is in building science and technology. I understand how combustion exhaust doesn't always behave inside of homes. Minimum fees are minor point in big picture.

  • geoffrey_b

    Two weeks after California's largest utility PG&E filed for bankruptcy protection (marking its second bankruptcy in 20 years), Bloomberg is sounding the alarm that California's two other large electric utilities are just one wildfire away from bankruptcy filings of their own - a fact that was underscored last month when S&P slashed their credit ratings to near-junk status.


  • Elmer J Fudd

    I mentioned replacing BOTH of my furnaces.

    No, I'm not in a mobile home. Would you think a mobile home would have two water heaters and two furnaces? PG+E has no monthly service charges, no per day minimum fee for gas and the one for electricity is irrelevant, as I said before. At my second house in another part of the state, served by a different investor owned utility, there are similarly no monthly or daily service charges. I'm sure it's different in other parts of the county but your pretense to tell ME what I pay and for what is astounding. You're wrong, wrong and wrong.

    You recommend minisplits for an existing 4600 sq foot 5 bedroom house with hard metal ducts? In one of the more expensive electricity areas in the US?

    Your information and recommendations are unique but not in the way you would like.



  • PRO
    Springtime Builders

    Elmer, your posted bill shows rate schedule G1T, the T being designation for mobile home service. Maybe you posted the wrong bill by mistake. Most single family would be labeled G1 and is subject to a minimum per day transportation fee. (Minimum Transportation Charge (G-1 Only) 2/ (per day) $0.09863) It's such a low monthly minimum that PG&E may roll it into the therm pricing or include it as customer charges somewhere else, possibly in electric bill. The vast majority pay more for zero gas usage.

    Who knows what actual situation is but for someone in your climate considering furnace vs heat pump, using the heating home calculator, a high efficiency ductless heat pump seems to have edge over NG in simple energy costs. Using 22 cents per kwh and $1.18 per therm I got $1355 for a year of NG furnace and $1256 with a ductless heat pump assuming 400% efficiency (COP 4) a seemingly fair input given San Fran's average temps.

    Not saying ductless heat pumps make sense for all projects, but they can have lower heating costs than natural gas, even in high priced electricity markets. Dare I say they are always cheaper to operate than propane and safer too.

  • Elmer J Fudd

    Sorry, you're really clueless.

    But you've done me a favor. In future threads when you try to spew your made up nonsense, I can link to this thread for readers to decide how much or how little you know about what you say.

    For other readers, don't be confused by the 400% efficiency stat that's being quoted. Percentage efficiency of a heat pump is relative to resistance electric heat. An electric resistance heater, the most expensive and most inefficient way to produce heat, is defined as being 100% "efficient". A heat pump, other than at colder temperatures, can by comparison produce 3-4 times as much heat from a given amount of electricity. So, 300-400% efficient WHEN COMPARED TO RESISTANCE HEAT.

    This is a completely different measurement than when talking about the efficiency of a water heater or a gas furnace. If a gas furnace is "95% efficient", that means that only 5 percent of the heat energy in the gas is lost and not used to heat air passing through it. The "percentage efficiency" of a heat pump and the "percentage efficiency" of a gas appliance are completely different numbers, completely different measurements, and are not comparable one to another.

    Our obfuscating friend has offered a calculation using wrong cost numbers for my area. I'm done with him.

  • Elmer J Fudd

    A question I've been meaning to ask - I'm retired and have plenty of time for hobbies, fun activities, travel, and occasional visits to this forum.

    How does an active contractor have time for this? The busy contractors I've worked with (and I just finished a fairly major project with one) seem to work 16 hours a day.

  • PRO
    Springtime Builders

    Oh come now Elmer, we are rained out today so my office time allows for two little forum posts. I think it's fun! I blame it on growing up with too many Saturday morning cartoons :)

    For those curious about the 400% (COP), the home heating cost calculator allows you to input this number by clicking on box to right. The default for Maine climate is 293%. COPs are available at NEEPs database. The calculator makes these fuel cost comparisons very easy.

  • weedmeister

    Tiger used a COP (Coefficient of Performance) of 3.0, which is not a bad choice. One should note that the COP of a heat pump will vary with temperature, lowering as exterior temperatures drop.

  • PRO
    Springtime Builders

    3 is probably a good average for OP's Ohio, maybe representing high end of an American ducted system or low to mid range of what's possible with high efficiency minisplits. San Fran is a world away from Ohio and Maine. I bet some equipment could hit over 5, majority of time in that climate.


    I highly recommend learning more about right sizing equipment to double check builders and HVAC contractors. I wouldn't build a new home and size the mechanicals without the help of a Manual J, third party HERS rater or mechanical engineer comfortable with the newer options.


  • David Cary

    Efficient is a word with an exact meaning. Elmer - you stated that electric resistance is the most expensive and inefficient way of producing heat. That is just wrong and an incorrect use of the word efficient. It really looks bad since it was in a post where you were accusing someone else of being "really clueless".

    Whether electric resistance is the most expensive does depend on what you pay for electricity. Its efficiency absolutely does not.

    Heat pumps are a bit like electric cars. They may have some fossil fuel inputs but they will have less over time. A NG furnace will forever be powered by fossil fuels. That component of sustainability should factor into any decision. There will likely be a carbon tax in the lifespan of your HVAC equipment.

    2018 saw a record number of coal plant closures. Double that of 2017. Coal use is expected to fall 8% in 2019 and 7% in 2020. So every year the heat pump (and EV) gets cleaner. This despite the science deniers in the administration. The attack on science will not continue forever.

  • Elmer J Fudd

    David, you're building a new house to live in. Not a palace but a reasonable middle class house and you have an adequate budget and financing.

    Are you going to use electric resistance heating for heat?

    I believe the concept of "efficiency" for electric heating didn't come into use until the growth of heat pumps. Resistance heating was defined as 100% efficient, and then the energy efficiency of heat pumps could be expressed numerically as some multiple of resistance heating, the benefit and increased output coming from the different physics involved. Resistance = 100% is the baseline used for comparison measurement. It has no other significance to my knowledge.

    The dangers of coal plants have been known for decades, yet utilities in areas like yours (the South) have been permitted to continue using them. Yes, they're starting to be shuttered. 20 years or more too late.

    In my area, relatively much cleaner and less dangerous gas power plants are being taken out of service and shut down. We'll be paying even more than now for electricity but it is the right thing to do. The big challenge is storage for nighttime and other usage when the sun isn't shining.

    If you're interested, one of several storage systems in our state is the Castaic Power Plant, in service for many decades. Offpeak power is used to pump water uphill to a higher reservoir. It's then released when needed, and pumped back uphill to use again. There are a number of such water "battery systems" in the California mountains, though none are real large.

  • PRO
    Springtime Builders

    Yes, David will probably use electric resistance heat, but only as a backup or auxiliary to the heat pump. This can easily make more economic sense than installing a gas furnace. The high efficiency heat pump does most of the work and electric resistance is there for emergency or 1% design temperatures.


    I can think of two situations where electric resistance heating is good for the electric grid, handling excess renewable generation and addressing the night time storage problem. Electric tank water heaters are perfect for this and some utilities are offering incentives for people to install simple electric tanks and the controls to make this possible. Charge the storage tank during times of excess and still have plenty of hot water for times of high demand or upper tier pricing.


    Radiant floors or hydronic heating can work the same way. Charge the floor or hydronic storage tank during times of excess and have plenty of heat for peak demand hours.

  • David Cary

    When the vortex came through, I saw a 15 minute spike to 10kw.

    It wasn't record cold or anything but design temp.

    That was 2.5kw or 27 cents. I suspect I might hit $10 a year worst case.

  • PRO
    Virgil Carter Fine Art

    Old not very helpful information. And one "runs out of fuel" for heat pumps every time there's a power outage, in which case a stand by generator is needed. Ask me how I know...

Need help with an existing Houzz order? Call 1-800-368-4268 (Mon-Sun).