Heating and Cooling Plans Take a U-Turn

Sarah Palin

Turns out we’re actually not going to Drill Baby Drill.

A couple of weeks ago, in the midst of wrestling with some difficult cost-cutting decisions, Build and I met with an energy consultant to discuss the viability of equipping the new house with technologies like geothermal and radiant heat. My hope was to use both, in an attempt to be as green and comfortable as possible.

I had been told by a couple of local drilling companies that I probably only needed three 300-foot holes drilled, at $5000 apiece, to generate enough load to both heat and cool the house. Although $15,000 is a lot of money, it seemed like a good investment and the right thing to do, from an environmental standpoint.

To my dismay, however, the consultant was pretty sure I needed five holes, considering how many windows I have, and that the total drilling bill would be more like $30,000. If I was under budget or close to it, maybe I would have still considered it, but since I’m still substantially above where I want to be, it made sense to say goodbye to geothermal heat, unfortunately. I get the feeling this happens to a lot of people; swearing to use as many clean technologies as possible and then shuttering many of them along the way as costs begin to spiral. I look forward to the day when the cost of building green is not significant enough to even notice. That being said, building green is not an all or nothing proposition. Just because I’m not plunking down $30,000 for a fancy geothermal system doesn’t mean the house won’t be energy-efficient in many other ways.

The next decision revolved around radiant vs. forced air HVAC. Going into this meeting, I didn’t even think forced air would be on the table, as many people have told me that radiant heat is far superior. The problem, however, with radiant is that there is no built-in cooling. There is a “comfort system” they can build these days which runs cold water through the radiant pipes but it’s not really capable of cooling the house by more than a few degrees. Given the fact that so much of the west side of the house is glass and will transfer a lot of heat from the sun, it seemed necessary to have a full-fledged air conditioning system for those (admittedly rare) sweltering Seattle summer days.

Could we try and design a house which used breezes off Puget Sound to cool the house in the summer? Sure, but if it didn’t work so well, retrofitting for air conditioning would be difficult and expensive. Given that, the project now required full ductwork for a forced air A/C system. And given that, we were now talking about two totally separate systems for HVAC: radiant pipes for heat and forced air for A/C. Expensive, and arguably overkill.

On top of these complications, the energy consultant also warned me that radiant heat is not nearly as fast as forced air at changing the temperature of a house or a zone in the house. Radiant can take 2-3 hours to do its job while forced air is more like a matter of minutes. While this usually isn’t a big deal because most people keep their house at a relatively constant temperature, my house may present a difficult challenge because of all the west-facing glass (this is becoming a theme, I am noticing): on a cold, clear winter morning, it may be 30 degrees outside and the heating system would probably be cranking. But as soon as the sun hits the west glass in the afternoon, that could warm the house up naturally quite a bit. At that point, the heating system needs to ease up a bit. And then when the sun goes down, it needs to crank back up. Radiant heat is simply not as good as forced air for quickly adjusting to these sorts of things. And on top of that, radiant heat does not work perfectly under wood floors. It’s generally best under concrete, slate, or tile.

So anyway, with all of that to consider, I made the call to move forward with a natural gas powered forced air heating and cooling system. I may do a mini radiant heating pad to warm up the master bathroom tile, but that’s it. On the downside, it’s not as forward-thinking of an HVAC system as I was hoping for, but on the upside, it should be more comfortable, and it saves me probably $40k-$50k in total.

33 Responses to “Heating and Cooling Plans Take a U-Turn”

  1. Steve Says:

    Hey Mike,

    As I mentioned before when the first designs were in, with all that west facing solar glazing your house is going to be a real beast to heat and cool all year long. If the sun is out the house will overhead, even on a mild day. And now that you are considering forced air, the energy bills are going to start large and keep on climbing.

    Since the lot dictates a very poor design/orientation for energy efficiency, your only option is exterior blinds and a geothermal system. Think about the actual long term energy costs, not just the installation cost.

    Eventually you will want to sell this house. I think in 20+ years when people are going to purchase a home, energy efficiency will be a top priority and with forced air, yours will be a hard sell. But by then you will have installed solar panels and a wind turbine so you may be OK.

    I would love to see the Sustainability Label for your house with forced air A/C and all that glass.


  2. John B Says:

    I like radiant heat, well, just because I like it. Also, I rent & don’t pay the heating bill for the antiquated system in this house. However, forced air seems to have clear advantages in your situation and if you do throw up a wind generator or 2 in a few years with some solar panels you may be able to swap out your gas-fired furnace for an electric one and be super earth-friendly, (or, you could go with a wood-fired and at least be carbon-neutral, with a bit more work).

    Something that’s going to make a huge difference to the energy efficiency of the house is the type of glass, so you may want to get the most efficient glass possible. Also, you may want to think outside of the box. For example there’s a skyscraper in downtown Toronto that is covered in glass, but the glass has, I believe, a tiny film of gold in or on it. This film reflects light out during the day and heat in during the night and apparently, (this is 8th-hand information), paid for itself very quickly. Also, it looks cool. Imagine the view of your house from the water with the sun setting on it, sining in golden brilliance!

  3. Chris K Says:

    Are there any sort of “green energy” tax credits you could qualify for that could offset the cost of the geothermal system?

    If there are, it may be worthwhile to verify that any sort of credit + how much you’d save monthly on your energy over forced air for the amount of time you plan on living in the house would save you, if anything. If it’s close, then it may still be worthwhile to do the upfront geothermal cost, as that’s one thing you likely can’t do later.

    Though, as John says, supplementing the forced heat setup with a solar or wind-based power source could offset the cost for that, and I am almost positive there are some tax incentives for wind turbines, etc.


  4. Mike,

    For the radiant boiler system look into utilizing the AO Smith Vertex H20 Heater as your boiler unit. Discovered after installing it they are actually a 100,000 BTU boiler. So a 5,000 SF area may work. Radiant is wonderful cost effective heating solution. For cooling maybe look into cooling with a smaller room-by-room unit and then possibly designing a way to utilize the cool air with venting or something. Your house may not lack the heat. Is there a way to utilize geothermal without drilling, in a loop system in the yard? We are lucky our client is so mild.

    Thank you very much for blogging your adventure! Cannot wait the see the finished house, the design is wonderful!


  5. Mike D. Says:

    Steve: Exterior motorized blinds are already in the specs so that will allegedly reduce the solar gain effect by something like 60%. Given that, I’m not *super* worried about the cooling situation, but heat is definitely an issue. I’m definitely going with the most efficient glass I can find, but would love to know what my delta in heating costs is with the west glass the way it is. The thing about it is that I wouldn’t really be comparing “no glass” to the current amount. It would be more like one story of glass on the west side vs. two stories. The rest of the house seems pretty normal as far as amount of glass. If the delta there is like $50 a month, then that would be a concern, but it seems like it would be quite a bit less than that. But then again, I’m just guessing. I should probably get a second opinion from another HVAC person. Was going to do that anyway. Also, with regard to forced air being a tough sell in 20 years, I don’t know about that. I would bet over 90% of houses are forced air. I think in 20 years, new homes will have better systems in them, but most home sales will still be older homes. Also, as soon as solar becomes viable (which may be a loooooong time), the value of a geothermal installation drops. It’ll still be a perfectly fine way to heat/cool, but its marginal value over the next best alternative (solar) will be zero.

    John B: Yep, type of glass will be super important.

    Chris K: Yep, there are definitely tax credits but it’s in the order of several thousand dollars. Not really enough to make a dent.

    Ryan: That’s a good idea. I thought about doing the room-by-room A/C, especially since I *really* only care deeply about it in my bedroom, but it just seems like something that once you make the decision not to do a house-wide system, there is no turning back. A lot of my trepidation about the whole HVAC thing is that I feel like I’m making a very important, largely irreversible decision. I could probably switch courses on the geothermal thing anytime between now and the next few months, but the forced air vs. radiant thing doesn’t seem too iffy at this point. Radiant would require the lack of whole-house A/C and that, to me, is a bigger downer on both me and potential future buyers than lack of radiant heat.

    Thanks for the great thoughts everybody…

  6. Steve Says:

    Good to see you are getting the exterior blinds, they will help considerably as long as you keep them down from 2:00 pm until dusk on a sunny day.

    It’s too bad you didn’t give the heating/cooling needs of the design more thought early on. Basic passive solar concepts suggest the main width of the house be placed on an east west axis. Solar glazing (windows) for the south side should be about 17% of the total square footage. West glazing should be 0 to 2%.

    A creative solution would have been to turn your house more onto the east west axis and have covered entertainment areas on the west side connected to the house by sliding glass walls that take in the view but don’t allow the sun to penetrate the house.

    I found your design process backwards on this project, you made the house look cool and then worried about function later. The thinking is more inline with a subdivision developer. Building a new home is an excellent opportunity to take advantage of new techniques and concepts. To say solar isn’t viable shows little or no regard for the total efficiency of the house. There are many homes today that are off the power grid using solar and wind.

    Have a look at 360 Winnett, it’s another custom home blog, but has much more consideration for the toal package.

    Ed Begley would set you straight.

  7. Mike D. Says:

    Steve: I would say we are still pretty “early on” and I also wouldn’t say that we had any choice as to the orientation of the house. It’s going to be built on an existing foundation, and for that matter, I’m happy that it’s oriented as it is (to capture the view). If you’re saying that west glazing should be 0-2%, you’re also reducing the value of the house by 50%. Possibly more.

    While you say my design process is backward on this, I say that yours is not only backward, but completely non-sensical in almost every way that matters to most people. Let’s see… buy a beautiful plot of land with one of the best west-facing views in Seattle and then not only turn the house away from the view but also place large sheets of drywall between it and you? Mmmkay. Sounds like a nice house!

    Energy efficiency is not the point of building a house. It’s a consideration. The parallel in the web development world would be to build an application that hardly anyone really loves but is engineered perfectly on the back-end. To me, this is pointless. I’d much rather concentrate on creating the most useful, compelling application I can and then make sure the engineering is as efficient and sound as possible along the way.

    And before you go on about how viable heating a house with solar is (especially in Seattle), you should do a little more homework than following a blog post to TreeHugger. Whereas geothermal would cost an extra $30k-$40k upfront, solar would be more than double that. Solar-thermal is becoming a reasonable way to heat your water, but PV panels right now? Not even close.

  8. Steve Says:

    Did you not look at the link to the covered outdoor entertainment area for your western exposure, seem a little different than drywall huh? The point is to stop direct sunlight from entering the home on the west side.

    What source are you basing the “PV panels right now? Not even close” statement on? And to imply that the treehugger link is only research I have done on the matter is a bit much. I can give you 30 more links and lots of books if you want.

    Ask Build what it would take to make your house LEED certified. You wouldn’t get past the first point: Lower operating costs and increased asset value.

    If “the point is to build the most comfortable” house you can, should you not consider how livable it is without consuming huge amounts of energy to make it so?

  9. Mike D. Says:

    Steve: I did look at that link, yes. Firstly, it doesn’t jive with your 0-2% west glazing statement. It’s still west glazing. Secondly, its main benefit appears to be the overhang over the glass, which I already have to some degree (not to mention the exterior shading). Thirdly, again, the house is not a blank slate in terms of what goes where. The number one priority is using the existing footprint in the most useful way possible, which I think we’ve accomplished quite well. And by the way, the deck on the north side of the back of the house may eventually become a covered outdoor area anyway. Can’t do it on the south side though.

    If you’d like to read further on the state of the solar panel situation, I recommend this 38 page report from Cal Berkeley from January of this year. It examines the realities of solar from even the most well-suited of markets (very sunny areas) and comes to the conclusion that most other people have also come to: solar may indeed be the future, but it definitely isn’t the present… especially at its current price/output levels. The possibility of solar becoming cost effective in the next 10-20 years is all the more reason not to sink a ton of money into geothermal right now (although I still want to and will probably seek a second opinion on geo costs).

    With regard to your last paragraph, yes, I definitely agree that “comfort” includes how much energy (and cost) it takes to operate, but plopping down $80k-$100k on a solar system essentially ensures that you never make that back for the rest of your life. In order words, at that price, there is no break-even point. Much better to wait until they are more like $20k-$30k and add them on later.

  10. Angelo Says:


    Very nice project and blog! I feel for you on the mechanical decisions. We went through a very similar experience – we thought we would definitely be going radiant, maybe even geothermal, and ultimately ended up with high-efficiency forced air and an on-demand water heater instead.

    Here is our history (go to the bottom and work your way up):


    Until some of these systems become a commodity item, they are NOT cost effective in our experience. Especially If you want build under $200 a square foot. We focused on a very good exterior envelope (SIPs and triple pane windows) and Manual “J” calculations to size the furnace to get the optimal setup. Even solar panels didn’t make it in – we did rough-in the electrical for them and will wait for the prices to come down and better rebates.

  11. Steve Says:

    Yes, what I failed to mention was Direct Gain solar glazing, west windows hit by direct sunlight. Which your house has a ton of. It will overheat but I can see that isn’t a priority for you.

  12. Mike D. Says:

    Angelo: Thanks! I’ll probably end up with something very similar to what you have (high-efficiency forced air and on-demand water heating).

    Steve: Thanks for clarifying. I wouldn’t say it’s not a priority at all but this is Seattle we’re talking about. On most days, I would welcome the transfer of heat through the glass, and on most days, the clouds provide a good barrier from the sun anyway. That combined with the exterior solar shades make solar gain much less of an issue for me than heat loss in the winter. To me, that’s the big thing to keep an eye on. Supposedly, forced air is better at minimizing the noticeable effect of these because you can put the vents near the glass.

  13. John B Says:

    My grandmother used to live on an island on the west coast with no electricity, gas, or anything, and from what I remember, a while ago, the wind provided a LOT more power than the solar. Heating the house, in the winter, using the power generated by the solar panels, would never work.

    However, if your hill is as windy as I expect it may be, a couple of good wind generators may give you a chance. Maybe not a good one, but at least a chance.

  14. Mike D. Says:

    John B: Yes, I definitely agree about the wind. I haven’t looked into actual energy generation via turbines, but I’m definitely of the opinion that the natural breezes coming in off the water are capable of doing a lot of natural cooling on their own. Hopefully that will limit the amount times I need to turn on the A/C.

  15. Laura Says:

    This may be a silly question, but is there any “hybrid” cooling options? Like drilling less than five holes for geothermal and using those to augment the HVAC? It is building two systems, but maybe the geothermal contribute enough to your heating/cooling systems to make it worthwhile…

  16. Rich Says:

    Mike, Here is a link for a wind turbine company whose product just might work for your project.



  17. Mike D. Says:

    Thanks Rich. Good looking stuff. Their wind calculator unfortunately thinks my wind potential is low though. :|

  18. Mike D. Says:

    Laura: Yeah, not a dumb question. I think it’s definitely possible to do something like that. If not a hybrid system, it may be possible to only drill three holes and have “enough” A/C but not “more than enough”. In other words, maybe you could move 90 degrees to 75 degrees, but not to 68 degrees. Something like that. Will look into it.

  19. Mike Says:

    I hesitate to leave this comment as I’ll essentially play the part of devil’s advocate. Therefore, I’ll first write that I’m impressed with and admire your motivation to build an environmentally responsible home. I completely understand the enormous responsibility that you’ve willingly undertook with the cost, time and effort to build the home. However, it seems one simple option that’s not under consideration is to alter the design to include less glass. That seems the crux of the problem. Deal with that, and many of these subsequent issues aren’t quite as monumental.

    Perhaps you’re too far along to make alterations to the design. If so, ok. I can understand a lack of enthusiasm to revisit that process. Yet, some changes to the facade might solve the dilemma while not incurring much hassle on the design side. Maybe not, though, it’s just a thought. I don’t know the exact pros and cons a change like that creates for you- they are certainly personal and subjective issues which I don’t mean to second guess because I have no grounds upon which to do so. Instead, I offer my outsider’s perspective as a reality check. I suppose one problem anyone in your situation faces is the trap of becoming too close and emotionally attached to the subject matter (which is perfectly understandable) and no longer able to see the bigger picture.

    I’m forever a fan of simplifying problems to their essence and basing decisions on the results of that exercise. For what it’s worth, that’s my outsider’s perspective. At any rate, I think the house is great and you clearly bring a thoughful approach and I appreciate your willingness to share it with the wider world.

  20. Mike D. Says:

    Mike: In my mind, there are two potential problems with glass: letting sun and heat in in the summer time and letting heat out in the winter time. Given that we’re going to be using an exterior sun shade, that pretty much eliminates the first problem. As my architects pointed out to me, it’s pretty much like having a wall there instead of glass, but you can move the wall out of sight whenever you want. So I’m cool with the solar gain part. The other problem — that of heat loss — is one I can temper with high efficiency double or triple paned glass, but that doesn’t exactly eliminate the problem completely. What I’d really like to know is, what is the delta in heat loss between one story of glass (which I’d have anyway) and two stories? I’m not sure it’s very high… but I could be wrong. If it’s an extra $10-$20 worth of heating per month in the winter, I’d say that’s fine. If it’s an extra $100, that’s different. Am curious as to how you go about figuring that out.

  21. Steve Says:

    Hey Mike,

    I can take a simplified stab at this to get you started.

    To calculate heat loss you need the U values and square feet of all external facing materials, windows, ceilings, walls, doors etc. The U value is BTUs lost per hr, per square foot (U=1/R). For a rough calculation you also need the temperature difference between the interior and exterior of the structure. You can use two figures, one for the cooling season, one for the heating season. This is very important, because heat transfer increases exponentially as the temperature difference increases. If the temperature is equal on both sides, no transfer, if it’s 30 degrees the transfer rate is obviously much higher.

    There is also heat loss for ventilation (heat exchangers reduce this), door traffic, and voids in construction where different materials meet. This is where older homes perform poorly. Today with SIPs, spray foam etc you get a very tight structure so the heat loss in voids is minimal.

    Now if you look at your windows, a quality triple pane Low E/Argon gas filled, fixed, window comes it at around R=5 or 6, U=1.7. Supposedly there is a krypton filled window that performs at an R=10, U=0.1 but it probably comes with a Superman price tag. A wall of SIP construction is rated around R=25, U=0.04, 4 to 5 times the performance of glass. Straw bale (I know, crazy idea) comes in at a massive R=48, U=0.02.

    A couple other considerations:

    • Think about the home’s performance in summer— it’s not just about heat gain from the sun—even with the shade down, there is substantial heat transfer through the windows putting more load on your cooling system.

    • When you have a vaulted room heat moves quickly to the ceiling, forced air adds to the air movement, making it seem breezy so you end up increasing the temperature. Radiant heat travels slower, through you for a better comfort level. Unless you are on the couch, then you need a blanket or small gas insert, wood stove, etc. (It does tend to warm up the furniture though).

    • If you spend more on a geothermal/radiant system, you may not get your money back through operating costs, but the house will have a higher resale value.

    • If you can, check out homes with these different systems in the middle of winter to see what you prefer.

    There are all kinds of tables online to plug in your numbers for heat transfer.

    Hope this helps.

  22. Mike D. Says:

    Thanks Steve. Good info.

  23. Rich Says:

    Mike, When I saw this I could not help but think of your project.



  24. Mike D. Says:

    Rich: Thanks for the link. Very interesting. I’m *definitely* going to have a multi-zone thermostat system to help handle the different loads of each room, but the idea in that Norwegian house is nice — set things automatically based on known load variables.

  25. Liam T. Says:

    Hi Mike,
    I represent HVAC equipment for the commercial markets. I can help you out with design of equipment, as well as hook you up with some consulting engineer friends of mine, that would have great insight on the types of systems you are looking at.

  26. Steve Says:

    Hey Mike,

    Have a look at this house, similar orientation to yours: on the water with west facing glazing. They are using geothermal/radiant heating & cooling plus solar.


  27. Mike D. Says:

    Steve: Thanks… I just caught that on Contemporist today as well. Truly, truly spectacular. I love everything about it, and it’s a great example of what you can do if money is no object. Seriously, it seems perfect in every way.

    Cost-wise, it’s probably at least $400 per square foot, and at about 7000 square feet, that’s $2.8m in construction costs plus maybe $1.4m in soft costs (using the 2/3rds 1/3rd rule), so that’s $4.2m. My math and estimates could obviously be off, but that’s many multiples beyond what I’m spending.

    Still though… its a great, great example of the frontier of energy efficient luxury homes. If it costs that amount to build now, it will cost much less in 5-10 years.

  28. Hi Mike, I hadn’t been to your blog in awhile…thought you’d be further along.
    If you haven’t decided on a HVAC system yet, you might want to consider an Air to Air heat ump with a gas furnace auxiliary back up (all one unit).
    I looked up Seattle’s weather (http://www.beautifulseattle.com/clisumm.htm), and I think an air to air heat pump would work fine for your situation, seldom utilizing the auxiliary back-up.
    I’ve used heat pumps in building for over 25 years. They are great once you get used to the cooler temperature air output during the heating phase.
    The technology has improved to the point that they will operate to well down below freezing without calling for the auxiliary back up.
    Check all this out with an HVAC supplier/installer…or have your builder do it.
    Here’s a link to a blurb about the Bryant Hybrid: http://www.bryant.com/news/pr-20061025.shtml. (I’ve always used Trane)
    Good luck, Merry Christmas & Happy New Year.
    Carl Heldmann

  29. Mike D. Says:

    Carl: There’s no need to rush through design and planning when you can’t even break ground until the spring anyway. Thanks for the heat pump info… that’s probably indeed what we’ll be using.

  30. Darin Says:


    Great Blog! I’ve been sifting through the information and you’ve been doing a great job documenting everything. As an architect, I’m always very curious what’s going on in my client’s head’s.

    As a response to this post, we’ve been specifying radiant heat which seems to be the most comfortable heating system. In addition, we use an HRV or ERV to both supply constant fresh air, as well as temper the air from one area of the house to the other. This way, the temperature at the lower level of the house is very close to the upper level(s). In addition, we have been roughing in for a ductless mini split heat pump that can be fully installed at a later date. The heat pump is a very efficient way to both heat and cool a house. It’s ductless and is very efficient. Because we never really know exactly how much cooling we’ll need because comfort is alway relative to the specific occupant, this gives our client’s flexibility to tune their house to their own level of comfort. Another advantage of the heat pump is that you can quickly change the temperature in the air while the radiant system catches up. In addition to these measures, we do our best to design the house to not need any systems at all…ultimately, we hope our clients never need the heat pump.


  31. ashish aleti Says:

    Hi Mike,

    I wish i had stumbled across your blog/website before we started our house construction. We are building our home up in mukilteo facing the puget sound, and so is our home with a modern theme and lots of glass. I did notice that you have 20+ foot ceilings in your living room. When you decided to go with your HVAC system, did ever a conversation come up with your HVAC contractor to install a huge fan over the great room/living room, to push the warm air down? (e.g bigassfans.com) our contractor is suggesting to put a 8 foot wide fan up there, though its practical, wife doesnt like it. Do you find uneven temperatures at the lower level (being slightly cooler/comfortable temp) and the upper level/mezzanine being at a warmer temperature? or do you have a system which pushes the warm air down without using a fan?

    please let me know?


  32. Mike D. Says:

    Ashish: Hmmm, I would say that unless you like the look of a “big ass fan”, you probably shouldn’t get one. We don’t have one and never really considered it. Nor did anyone tell us we should get one. We have plenty of vents in all three levels of the house so air is blown where it’s needed, when it’s needed. We have an damper system paired with the heat pump/furnace that can open or shut the flow of hot/cold air to each floor independently. That might be helping with the temperature evenness. If we couldn’t couldn’t each floor independently, I could see how that might waste a lot of energy and/or create hot/cold zones.

  33. Ashish Aleti Says:

    Ah finally found the topic i was looking for. Thanks for the information Mike. we do have right number of vents to heat the area, so i would say bye bye fan.