Timothy, with any project, you want to have an HVAC blueprint, and that will give you apples-to-apples bids. For a project like yours you would like to have an HVAC design professional (like Energy Vanguard) on board, which will get you the right size and type of systems for your structure and climate.

Even better, if your architect/builder did not put emphasis on performance of the home’s design, firms such as EV will be able to suggest changes in your building envelope that might bring you down a few tons, and get you more comfort, even if you already started construction (well, it depends). Comfort /= system size (that’s a not-equal sign), almost never.

And before you go all natural gas for your heat/hot water, open your mind to other options and talk to experts (your builder, bless his/her heart, may or may not be one).

We’re building a large custom home and one ‘expert’ HVAC bidder recommended three 5-ton systems and one 3-ton system, for a total of 18 tons… the home is 13,700 sf, so wouldn’t a few 5-ton systems be necessary to cover the square footage?

We also have a bid for a geothermal system with one 6-ton pump and one 4-ton pump to cover the entire home… conveniently missing the 5-ton no-go zone… but interestingly concluding that 10 tons are sufficient, compared to 18 tons for the other guy.

Man it’s hard to get apples-to-apples comparisons…

Thomas: That’s great to hear that you’re finding more contractors willing to go beyond the oversimplified square footage calculation. People often ask me—in fact it happened at one of my book tour events this week—if things are getting better. When I hear this kind of stuff from builders like you, it gives me more reason to answer in the affirmative.

Glenn: What you’re talking about is a split system refrigerator. It’s certainly possible to do that, but then you’d have an appliance that suddenly needs more maintenance. Current refrigerator design makes it a package unit, with everything in the same box. No installer can mess it up by making refrigerant line joints that leak or putting in the wrong amount of refrigerant. But if you turn it into a split system, you introduce the potential for a lot more maintenance.

The benefits just wouldn’t justify the extra cost and potential drawbacks. Modern refrigerators are pretty darn efficient these days, using only about 500 kWh per year or even less. It doesn’t add a lot to the cooling load, but it does help with heating.

And as Chriss Heenan said, you can’t just put the standard fridge outdoors because it’s not designed for those temperatures.

Greg: Sounds like you did a great job getting the systems downsized from what many contractors want to install. I’ll bet it’s a lot more comfortable, too.

Scott: I’m in total agreement!

Chris: Bravo! Get ’em off on the right foot.

Mike: Yeah, a while back I wrote an article titled Air Conditioner Sizing Rules of Thumb Must Die.