My Net Zero Journey (spoiler alert: it’s not over)

I’ve been sweating about climate change for a while now. I’m part of an artists group bringing awareness to these issues and I am also a member of The Pocket Change Project, the Eco committee of PCA whose mission is to help our wonderful neighbourhood fight climate change, largely through home retrofits.

So, naturally, I felt prompted to put my money where my mouth was when it came to greening my own abode. However, I wasn’t planning any major renos nor did I have some kind of rainy day retrofit fund gathering dust anywhere so I decided set myself the task of making the DEEPEST possible cuts in my carbon emissions for the LEAST amount of money.

The only thing I absolutely HAD to do was replace my shuddering clunker of an air conditioner- so old and inefficient is was possibly illegal. I had vaguely heard of something called an Air Source Heat Pump (ASHP) – which functioned as an air conditioner in the summer and a heating source in the colder months (when it basically became a reverse air conditioner). I knew that ASHPs were 3x more efficient than gas or conventional electric heating because they didn’t generate heat or cold just moved it from one place to another. So, I decided to investigate further.

I found it really tough to find good information on the internet – nothing that talked about potential GHG reductions anyway – I took webinars, scoured the Toronto Atmospheric Fund's website, looked at studies from the Toronto and Region Conservation Authority's model home where they test this kind of equipment. I felt like the Erin Brockovich of HVAC (heating ventilation and air conditioning acronym for all you non-nerds). After about 3 months of going down a ASHP rabbit hole, I finally made my decision.

There are ductless, ducted, dual fuel and fully electric ASHPs. But I finally settled on a ducted dual fuel heat pump to connect with my existing furnace. (This met my criteria for cheapest solution with the most impact).

A dual fuel ASHP is like a hybrid electric car – it runs on electricity for most of the time then switches to the gas furnace when it gets too cold out. I received so many contradictory opinions on how much of my heating load the dual fuel ASHP could take – some said it would heat my home down to -10, others said the same equipment was only good down to -1.

The Toronto Region Conservation Authority did a case study of Liisa's heat pump retrofit - check it out here

The reason this is so important to nail down is that Ontario’s electricity grid is very clean or at least, very low carbon (90% of our electric power comes from non-carbon-emitting sources) so electrifying our home heating makes a GIANT impact on our GHG emissions. The more heating from dirty gas my ASHP could replace, the better.

Not-So-Fun Fact: Pollution from heating buildings is responsible for 40 to 50% of the GTHA’s GHG emissions!

I have had my ASHP for almost a year now and here are my results:

It works great as an air conditioner.

It costs more to heat my house in the dead of winter but less in the shoulder months – resulting in a slight overall savings in energy bills.

It turned out that my existing furnace was too old and inefficient (12 yr old mid-efficiency gas furnace) to pair with an ASHP so even though it had a few more years in it, I decided to switch it out for a new high efficiency furnace. (If your furnace is a two stage high efficiency furnace less than 5 yrs old – you can probably connect it with an ASHP – you can also use a ASHP just as an air conditioner until you get a new furnace and connect it later)

It heats my home down to about -3.

I thought it was heating my home down to -5, resulting in a 50 to 60% drop in GHG emissions which I was super pumped about! I thought this because since I was home all the time because of Covid, every time the heat came on I would run to see whether it was the ASHP or Gas furnace (I’m a little obsessed, I know). And most of the time when the temp was -5 it would indeed be the ASHP that was working.

But when I got the numbers from the building scientist doing a study on my home – those numbers didn’t pan out – that GHG reduction results we more like 30 to 38% - still pretty awesome but…

So, I have more detective work ahead of me. I think something must be happening at night when there are longer, deeper stretches of cold. The furnace lets the ASHP try to heat the house for an hour and if it can’t do it, the gas will kick in instead – so maybe some smart thermostat adjustments and some more targeted insulation will get me to those deeper GHG reductions. I will let you know the results of my sleuthing.

Oh my God – this is so long – congrats for making it this far – just little farther!

I also did two other small retrofit projects. I insulated the back basement wall and corner of my house – the area where my energy audit identified that I was losing the most heat – also where I could feel icy winds blowing over my kitchen floor. And I got my home professionally air sealed.


Insulation: $2000.00
Air Sealing: $1200.00
High efficiency furnace and
ASHP: $10,000 (with tax and install)

Enbridge rebates: - $1600

Grand total: $11,600

These are the before and after numbers from my energy audits:
Before: 139 GJ/yr
After: 118 GJ/yr.

I am now addicted to GHG reductions. Every time I walk through my backyard and see my ASHP working away, I get a shiver of satisfaction.
It’s too late for me but there are now AMAZING rebates on ASHPs from the Greener Homes Grant. Seriously, amazing.

Next steps:

I am now investigating replacing my gas-fired water heater. It’s proving to be almost as complicated a landscape as ASHPs! Tanked, tankless, electric, ASHP, rebated, not rebated, leased, purchased! I’ll keep you posted!

You can contact me at [email protected] if you want to chat more about my experience. I love to talk about it!

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