The Pocket Change Project's Retrofit Coach, Paul Dowsett, made the ultimate green move with his own home recently - he got completely off fossil gas for his heating and cooling needs by replacing his gas boiler with two air source heat pumps. Oh, and did we mention he had three kinds of radiators - and kept them? Read on to learn how he did it.
Paul's Story - From Gas Boiler and Rads.... to Heat Pumps and Rads
By Paul Dowsett, Pocket Change Project Retrofit Coach
Is your house heated with radiators? Do you love them? I love mine!
Do you want to be much more comfortable in your home, have your energy costs stay the same - or maybe even go down a little - and know that your house no longer produces any greenhouse gases?
Do you want to switch your heating system from a fossil-fuel gas boiler to a hyper-efficient, all-electric air source heat pump (ASHP) …but have been told that you can’t?
That you’d need to get rid of your rads …and add ducts?
Well, not so fast! In my house, I have done just the switch that you want to do! And we used all of my original tanks, piping, pumps and rads!!
And, to make it more fun, my house has original, cast iron rads...
...modern, thin-walled rads, and...
...in-floor radiant heating.
And, of course, I now want air-conditioning, which I have never had before. So, how did we pull off this magic trick? “We,” in this case, is me and the great people at Goldfinch Energy and Switch Heat Pumps. First, let’s address the air-conditioning - as that was the easy part. Whereas heat rises, cool air falls, so it’s best to air-condition from the top of a house down. Where I most wanted air-conditioning was in my bedrooms and office on the upper floor where it’s uncomfortable to sleep and work when it’s too hot and humid. As I have an attic above the middle part of my house, with the bedrooms at either end, we decided to put a small air-handling unit in the attic to blow cool air into the bedrooms and office. The air-handling unit draws warm air from the ceiling and directs that heat outside through my smaller ASHP (yes, I got two, one for the top floor). In the winter, if it is ever necessary, this smaller ASHP can run in reverse and provide auxiliary heat to the bedrooms and office too.
The larger of the two ASHPs does my heating - through the radiators. This unit draws heat from the outside (yes, there is heat available outside, even when the temperature goes down to -30°C !), compresses it until it is warm enough, and then, through piping and a heat exchanger, deposits this heat into a hot water storage tank.
I have set my thermostats to 68°F / 20°C and the pumps send heated water from these tanks to the radiators until the thermostats reach the level I've set them at.
It's been a little while with my heat pumps now, and so far, my major observation is that I am getting a very even and comfortable heat - none of the temperature swings that I got with my old gas boiler - which usually roared to life and then overshot the desired temperature. Now my thermostat sits at a constant 68°F / 20°C.
I expect that I will find the ASHP much more “fuel-efficient” than the old gas boiler. Imagine slowly getting up to a nice, steady speed in your car on the highway and just staying at that speed - very fuel efficient - just that way that you were taught to drive. Instead of ‘gunning it’ to get up to speed, then slamming on the brakes, then gunning it, then slamming …just like my old gas boiler liked to ‘drive’. ASHPs are hyper-efficient because they don’t create heat, they just move heat from where you don’t need it to where you do. In summary, I am much more comfortable in my home, I anticipate that my energy costs will stay the same - or maybe even go down a little - and I’m really pleased to know that my house no longer produces any greenhouse gases. You can be too!! Ask me how!
Your friendly, neighbourhood Retrofit Coach.