You want a small and uncomplicated house, it's small and simple, and relatively cheap to heat and cool. You want big and complicated, the details for everything are big and complicated. And expensive. Sounds like you are building a hotel sized house. I wouldn't be surprised at a commercial level cost for the HVAC.

It's quite possible your HVAC folks have not kept up with trends and technologies and you are seeing that in their quote.

Finding the RIGHT installer is important here - your install looks WAY out of the ordinary.

Having just gone through this - you are headed for disappointment.

Who did the specification? You seem to have very specific brands and devices, tonnage, not exhausting air from the bathrooms, etc. Whoever does this needs to understand the vision of the system - and the designer of this system ought to have installers s/he works with that are competent.

If you have designed this yourself, you will likely be quite on your own to make sure it functions as you envisioned.

We're doing this now - our initial HVAC designer retired, and sold his company. After trying to use them, and then a follow on company, we've essentially taken over the role and commissioned the GSHP ourselves after Company #2 removed all the air from the lines. We're working directly with the manufacturer and so far so good. Some tweaking left to start up the water heating aspect of this GSHP but it's maintaining indoor air temp, ERVs are working as is the dehumifier and the vents that work when the kitchen hood turns on. But .... you need to be prepared to do this yourself.

Building a house is truly a luxury and even more of a luxury product when it is custom. The costs never end. We just spent another $10K this week to add some things that didn't get done during our build. This past year we spent another $40K to tweak the already expensive HVAC system that wasn't performing as designed. Note that I have a spouse that is very particular about temperature and will pay for that luxury. If I lived in the house alone, I would never have spent that extra $40K as the system worked well enough for me.

As far as HVAC, if you really want a high end efficient system, it all starts with the engineering design ... finding that person is the really hard part. Any HVAC company can install the average/generic system they have been doing for the last 40 years!

We have a large Mitsubishi VRF system with ceiling units and ducted units in the attic. Most HVAC companies do not have experience with designing/installing these VRF systems in residential homes, except for the few that have installed individual wall mounted ones, which doesn't make them experts in any way!

We always leave the design of the HVAC system to independent heating engineers, not HVAC installers. This eliminates a conflict of interest.

I am so confused. I called a local HVAC installer, one we have not requested a quote from but might yet. He was shocked by the 5 ton VRV ASHP. Apparently it’s nearly commercial. We had an engineer design the HVAC. We have it zoned, so there is an AHU on each level (3 levels).

I am also confused because this is really not a super luxury house or even a very large one… Our numbers show the square footage including the exterior walls which is misleading since they are quite thick due to insulation. Excluding the exterior walls, I think we have just over 2,200 sq ft between the main level and upstairs, plus 1,180 sq ft basement. This is about 3,400 sq ft including all 3 levels. Is this considered hotel-size?

The house was supposed to be very simple. It is basically a simple rectangle with gable roof, plus a small bump out in the kitchen with flat roof above.

We have such thick walls, with 4” rigid exterior insulation and then like 6” of fill. And an insulated slab. And R80 attic. I suppose there is a lot of glass in the design… but it is all very expensive triple glazed with the low-e coatings etc. We also have a ridiculously expensive wood heat source in the design. So I can’t comprehend why we need such a massive system nobody has ever heard of.

I do not understand why we had to hire an engineer for this if this is what we end up with. It’s like the septic. The installer was laughing about how over-designed it was since we had an engineer do that too. We had to truck in almost infinite loads of sand and overall they just said it was over-engineered by a factor of 3. The guy sounded so shocked about our ASHP sizing.

What climate zone are you in? A 5 ton unit for a very well insulate 2,200 sq ft home seems like over kill.

Climate zone 5B! The basement does have its own AHU so I guess in total the size is 3,400 sq ft… but with so much insulation and the ICF foundation I just cannot fathom this system design.

Could it have to do with the amount of glass? We have huge windows. But they are really good ones.

Anyway I emailed the engineer to just check if they are sure this is appropriate or if we can do a little ‘value engineering’. I saw Daikin also makes the heat pump in a 3 ton or 4 ton size and I imagine this would save a bit of money.

Wtth the insulation you are describing, a couple of incandescent bulbs might keep it comfortable. No point in over doing HVAC. You just end up with work out equipment rom short cycling, and an interior that is way too humid.

Where exactly are you, state or province? I think you said in the country. I would install a properly sized geothermal system designed for full load design conditions with integrated DHW production and no backup needed except for compressor lockout and no defrost modes either.

If you’re in the country you might be able to install a horizontal loop without drilling.

Will you have a water well?

IMPO

SR

Forget the engineer who is specifying 5 tons of hvac capacity for a well insulated and sealed 2200sf house in 5B. Start over with someone familiar with efficient home construction. Whoever specified your insulation plan should have access to a competent hvac person. Of call tech support for Daikin for recommendations.

You should have a CONTRACT with your CONTRACTor. If he underbid the HVAC, that's his problem. What were the specs for the HVAC in the CONTRACT?

We have a cost plus contract so basically their estimate was nonsense and we have to pay the extra 😭

Back to the sizing question....

Using a rule of thumb for sizing HVAC equipment e.g., SF/ton, can, and usually does, lead to erroneous results. I caution against concluding the OP's system is oversized or undersized based on any rule of thumb. Ditto for using a rule of thumb to justify disposal of the OP's engineer.

The OP's system is a heat pump so sizing needs to consider both the heating and cooling loads. Those loads are proportional to the indoor/outdoor temperature differential. Consider data for Buffalo, NY (IECC zone 5) for an example. Winter design temperature is 6F. Summer design temperatures are 85F d.b. and 73F w.b. So the indoor/outdoor temperature differential in winter is 72F-6F = 66F The indoor/outdoor temperature differential in summer is 85F-75F = 10F That's a factor of 66F/10F = 6.6

I suggest the OP asks his/her engineer to review the calculations to see if the assumptions are logical or not.

Yes, I think the engineer is good. Maybe too good. Our winter heating load design temp was -21ºC (-6ºF) and summer cooling load 31ºC (87ºF) DB / 22ºC (72ºF) WB. It seems like going down to 4 ton might be fine since it’s mainly based on the super cold winter days, it will be less efficient than 5 ton below -20ºC but I am thinking this does not matter so much as we will certainly be using the wood fire when it is that cold. I’ll see how much of a cost savings this is. If it’s like $1k or less, maybe it’s not even worth it though. And I want to keep the zoned system, it seems ideal having 3 individual thermostats. So we can set our upstairs sleeping temp independently from the main level or basement.

I get the sense that while we could definitely ‘get away’ with something smaller.. it is not really the most efficient or cheapest in the long run. Like, we could probably use a single 3 ton system with one thermostat. But ultimately we paid an engineer to do thorough energy modelling (a 13 page report) and it has been designed to be the most cost effective, low energy demand, most comfortable, in the long run. It’s just brutal now when the HVAC contractors seem to mark up the prices however they please because we are in a hot market in a part of the country with explosive population growth.

There has been a lot of attention on heat pumps in recent years here, everyone is getting one and the prices have skyrocketed. I can’t even imagine if our builder was doing fixed cost… budgeting $52k for HVAC and then coming in at like $70k? Yikes.

You can test the reality of the quoted prices by getting additional quotes-- although you may have a limited number of (if any) qualified HVAC contractors.

With respect to the size of the heat pump, you need to consider the crossover temperature--the temperature at which the heat pump's heat output is exactly equal to the heating load. Below that temperature you'll need supplemental heat. The incremental operating cost could quickly outweigh the incremental investment. Your engineer should be able to help run those numbers and make an informed choice.

Thanks! Yeah the local HVAC contractors are limited here (good ones especially) but I know there is at least one more I want a quote from as they have the brands we want so it will be comparable.

I know we have to pay for the time for our GC to get quotes but it’s just crazy to go like $20k over budget on HVAC alone so I’m hoping there will be a better option.

I know we could save $ on the vents, grilles and registers but I don’t really want ugly metal things everywhere as it’s all on the ceilings and there are a lot of them with both the heat pump and ERV.

" but it’s just crazy to go like $20k over budget on HVAC alone "

Not when the pricing was incomplete and inaccurate from the beginning. I am noticing a trend with your posts. The contractor you hired has "underbid" everything you have brought up. He did not underbid he deceived you and lied to you to get the project knowing at the end of the day you would be paying anyway.

The accuracy of any pre-construction cost estimate is a function of the time, care, and experience of the individual(s) who prepared it. There can be a temptation to take short cuts where the consequences of a bad estimate fall on the client and not the builder. But, the builder has a reputation to maintain and large cost variances don't serve that purpose well.

The OP's HVAC system is not the run-of-the-mill type. I infer that it's unfamiliar to local contractors. That raises a concern about their ability to properly install and maintain it. I'd include the engineer in the HVAC contractor vetting process.

A custom home, by definition, is designed to meet the unique needs of a particular client. What one client considers "over engineered" might be considered "basic builder grade" by another. The fact that the OP's HVAC system is upscale doesn't absolve the builder of his/her responsibility to produce an accurate pre-construction cost estimate, assuming they were provided with adequate information about the system at the time the estimate was prepared.

I think it all comes back to the architect. They did not provide the right information to the builder to prepare the estimate accurately in so many areas. The architect was responsible for coordinating with the builder and ultimately they just wanted to design whatever they design and kick us out the door. So the builder might not have had every detail in this instance for the HVAC. It’s not their fault, it’s the architects fault. Arch was coordinating engineering, and could have totally told the builder there will be not one but 3 heat pump air handlers. The architect designed the house and we’ve had to cut everything away to be remotely on budget. At the end of the day, we had a budget and we had our wishlist and requirements - the architect utterly failed to design something that aligns with the reality of construction costs. And this is why I think design-build firms will replace architecture firms. Maybe architects will still be doing the $10M projects, but there is no need for them in normal projects anymore. It’s too much of a risk for clients and builders to have designs not fit cost reality.

You take one experience and judge all architects? That speaks volumes about you.

It seems nearly impossible to design without checking the cost of everything, how do you do it? When costs are constantly changing and you have no idea how much items will cost… are you going to subcontractors and getting quotes during design? It’s almost less about architects and more about the process. I think an architect working FOR a design-build firm would be great. It’s not really about the architects, it’s the fact that they are divorced from the construction planning and estimation process.

"are you going to subcontractors and getting quotes during design?" Homes we build and remodel are produced following a design/build process. Each project is architect designed. We find it helpful to do some cost benchmarking prior to design so we're not designing a project that won't get executed. We begin estimating as early in the design process as is possible in order to inform the design. Our trade partners weigh at least twice in the process: we get budget estimates from the trades based on concept/preliminary plans, and pricing gets firmed up as design progresses through detailed construction plans.

Yes, this seems ideal. The problem with (our) architect (sorry Mark!) is simply that they don’t know the trades and honestly want nothing to do with them. The architects only want to deal with engineers, so they can chat over video call. They aren’t talking to trades. Resulting in architecture and engineering that kind of has no basis in reality because they are not the ones building anything.

To put it into words, I design with a general knowledge of the relative cost of material and assemblies. There are times when I will find out the cost of a specialty item if I do not know the extent of its cost. I designed one project with a gently curved sloped roof which I knew was and added cost, but I knew it was within budget.

Because of the nature of my practice I rarely get involved in the management of the contract between the owner and the builder because the owner does not want to pay for the services in a secondary home.

Ideally it is best to have a builder selected near the start of the design process so they can give estimates at each stage of the design.

Another factor is getting sufficiently skilled labor to execute the design. In the example I show above, the rough carpenter was smarter than me.

Forward the 13 page report to the tech support guys at Daikin. You need a skilled expert to create confidence.

I am not used to Daikin. When I look it up - it says it is for commerical applications. You live in a relatively poor rural area - did you think the installer would be used to Daikin?

Generally when using a new product, you have to quote for learning curve time.

Do you really want a learning curve on your house?

When someone builds a really tight house in the frozen north, it seems like electric resistance heat is often the best idea. Partly because a/c is not always needed and partly because body heat and the sun can provide the majority of the heating needs. You need a/c so you are getting a heatpump. In my mind, you should probably have 2 trane 2 ton units - one for each of the top 2 floors. Put electic resistance heat - like a fireplace in the basement.

KISS (not meaning to insult)

Daikin is the largest HVAC company in the world, I think. They’re familiar with the brand in the area, it’s more the exact model/sizing that seems shocking to them. But we have a zoned system which is definitely not typical. Most people have one system, not 3. You set the temp for the entire house, not by level. We could save a lot of $ by not having it zoned, but I’d think this would really need to be redesigned and ultimately it should have been designed during architectural design, not in the middle of construction.

I think it is mainly a communication issue… clearly they missed that the zoning and the flush drywall vents which need extra installation time and cost more.

Ultimately, if this was a fixed cost contract the builder would be eating this $20k overage because the specs clearly listed the equipment and the vents so it would have been up to them to estimate accurately. However it is our problem now.

I am thinking I can ask to simply remove the vents from the HVAC contractor’s job? All we need are rectangular cutouts the right sizes in the drywall connected to the ducts. Surely we can supply and install them for less than the like $12k the one installer increased their price by for the upgraded vents. They just pop in and you drywall mud around + sand down. I’d rather DIY that than pay $12k.

Hi, we have a Daikin furnace and air conditioner that was installed in October 2018. At that time, I had asked for a Trane or a Rheem system, because I was very used to those names, and they were replacing a Trane system that had lasted for 30 years. The large well-known company that installed it, said that the reason that they chose Daikin was because it had a 10 year warranty, and that was the best warranty in the business. For two months straight, we had a system that barely worked. The HVAC company was out at least once or twice a week for two months! And finally, in January 2019, they replaced the whole system, even down to the digital thermostat. Over the last five years, we have had Number 2 install break down every six months without fail. Sometimes it’s the furnace, sometimes it’s the AC. The most recent tech analysis, and it’s something different every time, was that the air filters were too good, and they were impeding the airflow to the furnace. he also stated that some of the parts that were in there were temporary parts that the system is shipped with, and so those parts (which should’ve been replaced early on in the ) are being replaced under warranty tomorrow, along with the digital thermostat that is not keeping time correctly. (I admit to not really believing any thing they say anymore.) Here is our plan. In five more years, when the 10 year warranty is up… We are going to buy a totally different system. Also, we have upgraded our electrical and, we have noted that the HVAC company no longer sells Daikin. Such a surprise… Not really… please DO NOT use Daikin no matter what you do.

Daikin is the world's largest manufacturer of air conditioners. Their brands include Amana and Goodman. The Daikin RXSQ60TBVJUA is a 5-ton residential heat pump. You can check out the spec sheet here:

https://bim.daikincity.com/item/vrv-life-outdoor-units/vrv-life-outdoor-units-rxsq_a-series/rxsq60tavjua

I’m sure there are people who have had issues with Daikin because it is such a huge company but I wouldn’t rely on anecdotal evidence… I think they make pretty good products and at the end of the day it still comes down to installation, I think. I like the idea of a long warranty from the manufacturer and a really trustworthy + reputable local installer.

I just can’t fathom upgrading the vents needs to cost > $10k so I might just want to remove this from scope. Wouldn’t drywall people technically be more suited for this work anyway?

This is what our engineer recommended and I love the look of Envisivents: https://www.envisivent.com/ plus the performance is good as they allow airflow unlike the other vents (Aria).

Envisivents are roughly 10x the cost of regular vents. While I don't see them costing $10k, it all adds up if you're getting the most expensive of everything. The Daikin condensers are mostly inverter systems ($$$). You might want to consider a single or two stage traditional ducted system from Goodman.

The Envisivents look really nice. They do cost a lot more than standard stamped metal grills. Installation will require additional work on the drywall installer's part.

It seems like this is a good system but the absurd price simply should have been discovered earlier rather than in the middle of construction. We like the variable speed compressor.

I am going to create a list of all the vents and sizes, and see how much the Envisivents cost since the prices are listed on their website. Seems easy enough to supply these myself and if I need to, I’ll install them myself. Otherwise I’m sure the drywall installer will do a good job. I think the fancy flush mount vents are just not familiar to the installers so if they have to give a fixed price, it’s going to be insanely high.

Our winter heating load design temp was -21ºC (-6ºF) and summer cooling load 31ºC (87ºF) DB / 22ºC (72ºF) WB.

Can you post what city location was used to determine these design temperatures? This is a big spread and I am curious where the range of climate occurs.

Do you have a copy of the load calculations? Have you reviewed it for the indoor design temperatures? Does the repost make sense to you? If the basement is mostly underground, then the cooling load should be close to zero, and the heating load should be lower then the first and second floors.

@mike_home yes I have the load calcs listed by room and I suppose they make sense. We have a bunch of huge windows, like 84”W… we’re in southern Ontario, Canada!

You can add up the individual heat loads to determine the overall heating capacity required.

Were the calculations done by hand or with a software program such as Wrightsoft? Even the most basic load caculation sofware will add up the heating and cooling loads. The HVAC installer should also do calculations for the duct work.

Heat pumps should be sized for the cooling load, and not the heating load. The reason is an oversized AC will short cycle and not do a good job of managing humiditly levels. Trying to size the heat pump in the cold climate of southern Ontario is not going to work well in my opinion. The HVAC installer should explain this to you.

I assume the engineers used software to do the calculations…

I was also wondering about the dehumidification issue with an oversized unit when it comes to summer cooling.

I think the reason they sized according to the cool temp loads is because below -21ºC the heat pump will need the backup electric heat to kick in. This is very inefficient and will cost a lot to run. So it is sized to provide enough heating. However, it is a Daikin VRV heat pump so wouldn’t this be able to run at a very low level in summer to provide cooling/dehumidification rather than being forced to run at a high speed, since it is variable?

"Heat pumps should be sized for the cooling load, and not the heating load."

This is true in general and in most locations but in a primarily heating location, with very little cooling requirements, it can make sense to size them on heating load. Still, there's always a balance between the two which is what backup heat is for.

Multi-stage variable speed equipment will help reduce the cooling size problem. However it is something to keep in mind when sizing the equipment. I am not familiar with Daikin VRV heat pump. You have to investiagate the cooling and heating ouput under all operating speeds. I don't think you will be able to not use any backup heating. The sizing of that is also important if you want to be comfortable on the coldest nights of the year.

Interesting. The original equipment schedule (5-ton w/ 3 AHUs) shows the following…

Heating Capacity

Basement: 12,240 Btu/h @ -20ºC (+5kW backup)

Level 1: 16,320 Btu/h @ -20ºC (+5kW backup)

Level 2: 12,240 Btu/h @ -20ºC (+5kW backup)

Cooling Capacity

Basement: 18,000 Btu/h

Level 1: 24,000 Btu/h

Level 2: 18,000 Btu/h

• I doubt we will use backup heat in the basement, that seems like more than enough for a minimally used space. It does not need to be super warm.
• I doubt we will need to use backup heat on level 1 because we have a radiant wood fire heater which might produce ~ 20,000 Btu/h and will only be used on the cold days, which conveniently is when the heat pump struggles. One load of firewood provides heat for 12-24 hours. Aside from how it might look on paper, for building code, I think during the coldest periods of winter we will use mostly wood heat on the main floor and if anything it will be overheated, so the heat pump let alone the backup heat won’t be as necessary.
• Some heat from the wood fire will travel upstairs, but we might need the backup electric heat on really cold nights upstairs.

How do I find out the heating/cooling capacities at different operating speeds? Also, is there usually a dehumidify mode on heat pumps or on an ERV? We don’t want it cold in the summer but we do want it to be dry!

"Heat pumps should be sized for the cooling load, and not the heating load." Not as such. Air conditioners need to be sized based only on the cooling load, because they only operate in that mode. By contrast, heat pumps operate in both cooling and heating modes. Accordingly, sizing a heat pump needs to consider both the heating and cooling loads as well as the particulars of the climate zone. If you size a heat pump for an application in southern Ontario, CA based on cooling load, it will be undersized for heating which will be the operating mode for the majority of the year.

Yes, after consulting some others it does seem like even the 5 ton might not be enough. Without the wood heat, we’d be using the backup electric in winter. It gets pretty cold here.

Although this is a cold climate heat pump, performance drops off when it’s super cold.

Our heating design temp was -21.2ºC and according to below, for this 5 ton model at -15ºC the output capacity is only 31k Btu - our total (non-simultaneous) peak load requirement is like 40k Btu - so now I understand why they did this heat pump. Sure, we could use a 3 ton unit, but the operating costs will be very high because we’d be using a huge amount of electric backup heat during the winter on the coldest days. This would add up quickly, and likely justifies the intitial investment in such a big system.

https://ashp.neep.org/#!/product/51530/7/25000/95/7500/0///0

However, one condenser with 3 indoor units might have other problems in terms of efficiency, which I’m not aware of.

" Ask the installer to provide a clear breakdown of both labor and equipment costs, including specific make/model numbers for each component "

Tejjy Inc. Almost a year ago, project is most likely done as it was new construction.