So one issue that I had been dealing with for the last few years is that fact that I needed a small furnace for a small heat load…
In other words, there has been nothing on the market for a long time that would satisfy the need for a small furnace.
Heat loads are getting smaller. We’re building houses tighter and tighter… we’re putting in more and more insulation. We’re replacing our old leaky windows with new Energy Star high efficient ‘tight’ windows. We’re wrapping our houses with house wrap (which makes them super air-tight) and we’re putting insulation in places that we didn’t in the past.
Did you know that approximately 40% of the heat loss in a house happens in the basement?
As we “tighten” up our houses and make them more efficient, naturally they need less heat in the winter. And, as we start to build smaller, super high efficient homes, then even the smallest furnaces on the market are way too big for the house.
A furnace must be sized to the house. A BIG house needs a BIG furnace…. a small house needs a small furnace….
It is absolutely imperative to NOT oversize a furnace. It will not run properly, will wear out sooner than later, and you will wind up spending a lot of hard earned cash just keeping it going.
One of the biggest challenges has been that even the smallest furnaces in each respective manufacturer is too big. Most manufacturer’s smallest furnace is a 40 to a 45,000 btuh furnace. In the past , when houses were less efficient, these 45k furnaces worked well in the smaller houses. But when we are building 600 sqft apartments with their own independent heating and cooling systems, then the heat loads are only 10,000 to 20,000 btu’s. That 45k furnace is more than double the size allowed.
I was lucky to come across Dettson furnaces while playing around on Google one day. Dettson is a Canadian company that manufacturers a small furnace. Now… not only is it just a small furnace, but it is a modulating furnace with a variable speed ECM (DC) blower fan motor, the best technology available in forced air gas furnaces. Dettson offers a 15,000 btuh and a 30,000 btuh modulating furnace among others as well.
A 15,000 btuh is the smallest furnace on the market that I am aware of… and to top it off, it is a Modulating Furnace with a Variable Speed DC Blower Fan Motor. Wow!
About a year ago, we installed two of these furnaces in a new build duplex. There were two self-sufficient apartments. The main floor unit was approx. 600 sqft but the basement was included in the heat load, so we’ll call it about 1200 sqft. It had a heat load of just over 16,000 btu’s. The second floor apartment (just 600 sqft) had a heat load just over 9,000 btu’s. As a result, we installed a 30,000 btuh and a 15,000 btuh furnace to satisfy the heat requirements without over-sizing.
They have been installed for a year now, and have worked great! No issues, no call backs, no late night service calls.
Here’s photo of the newest addition to the Dettson line-up. This is the new furnace cabinet for the 15,000 btuh furnace. You will see that it looks like an old desktop computer tower… and honestly it’s not much bigger than that. It is designed this way to fit into small closets, possibly over top of a washer and dryer, and still have room for an air conditioner coil and duct work.
A small furnace does exist, and it is welcomed with open arms.
Thank you Dettson for creating a great product that meets the needs of so many homes these days, and will be needed more than ever as we progress with more efficient, tighter homes in the future.
For more information on this small furnace, or other heating, cooling and indoor air quality demands, please contact me at 613-292-9573 or leave me a comment and I will get back to you…. or to have an email sent to you every time I write a new post, sign up to my newsletter at the right hand side of this page. I will not be pitching you, or selling anything. This site is for you, and to help you with making your home a little more comfortable for you and your family.
And yes… in case you are wondering… there are small modulating air conditioners that match these furnaces. Look for a post in the near future… or sign up!
John,
Just curious to get a bit more costing info on the Chinook modulating line and an idea of overall retrofit system cost into a 1960’s large duct hvac system… We’ve gone through a pretty deep energy retrofit, whilst adding on a secondary dwelling unit. 20k btu/hr & 11k btu/hr in main and sdu units… Dettson seems like an interesting approach, minus the likely higher sticker cost for the units given their relative awesomeness.
If you didn’t mind shooting me an email, I’d love to chat briefly.