What is the best heating and cooling system for a slab on grade home?


What is the best heating and cooling system for a slab on grade home?

Matthew Gioia Published: July 7, 2020, 11:03 p.m.Last updated: July 8, 2020, 4:46 p.m.

My fiance and I are building our first home. We purchased some basic house plans that are designed for a slab on grade home. I am really leaning towards slab on grade for the aesthetics, savings, as well as for environmental reasons. I live in New England and our winters are consistently below freezing and our summers frequently hit the high 80s and low 90s with bad humidity. Based on these factors, what type of heating and cooling system should we be looking into? I feel like if we go with a slab on grade we would almost certainly have to get radiant floor heating otherwise the exposed cement would get very cold in the winter. With that said, we would most likely also want to get some form of forced air system to heat our second floor as well as provide cooling to both floors in the summer. The forced air would also help maintain air quality in the home year round.

The above system in my mind would be ideal, but it also seems expensive to have both radiant floor heating AND forced air, especially when one of the reasons we are choosing a slab on grade is to save some money.


Responses (3)

Matthew Gioia
Matthew Gioia July 8, 2020, 4:56 p.m. Reply

Thank you for all of the fantastic information above. Slab is cost effective and a good start for an eco home. But do you think having both radiant floor heating, ductwork, heating/cooling systems heat is a bit redundant? Wouldnt having multiple systems to heat remove any cost savings that we gained by going with the slab?

Mike Reynolds
Mike Reynolds July 9, 2020, 9:52 a.m. Reply

I don’t think its redundant, partly due to how it impacts comfort. As you say, a slab is a more affordable way to build an efficient house than a basement, so you’re ahead of the game budget-wise. If you were to re-apply those savings to efficiency and comfort I think you’re still ahead of the game financially, but with a more comfortable and durable home. Maybe not with a cheaply built basement that will rot inside a decade, but certainly with a well built and insulated basement since that’s  more expensive to do than the way almost all homes are delivered by developers.

And here’s my final pitch - on an unheated slab on grade, no matter how well-insulated it is it will be cool on your feet, so I personally consider it part and parcel of a slab foundation simply for quality of life more than anything. The added benefit is resilience, in that you have a large thermal battery to store heat and help balance temperatures, which is great during a short power outage to stay warm and it can help you ride out a short heat wave without needed AC. And the trade off, is that you pop an air conditioning add-on to your ventilation equipment, since any radiant heated home needs an air exchanger to remove moisture and provide fresh air for occupants. I think any financial differences there may be in build cost are outweighed in long term operational costs, and it’s just a nicer home to be in.  Can you tell I don’t like basements? ;-)