Oh we pumped it up alright!
So much so that it inspired me to post this song from the good Elvis:
Why are we so pumped? We’re now the happy owners of one Mitsubishi ductless air-source HEAT PUMP!
This is the indoor condenser unit "head" of our new Mitsubishi 15,000 BTU Ductless Mini-Split air source heat pump
Our original reno plan had not included a heat pump. We were planning to use just in-wall electric heaters scattered throughout the house. Electricity is 100% efficient right? So how can you get better than 100%? We knew of the conventional heat pumps that run through an existing furnace and ducting system, but we wanted nothing to do with keeping our ducts or furnace. Not only had we already “sold” the furnace real estate to our new powder room, but the existing ducting was full of rat crap (thanks to a breech in our exterior defenses last winter) and I could not think of a way to clean out the ducting so that any air coming through it into the house wouldn’t smell like rat urine.
Oblivious to the existence of the ductless mini-split type of heat pumps, we went into our initial home energy assessment with the idea that the best we could do (within our means) would be to go the route of the various electric heaters. We were wrong. At our initial energy visit the assessor made a number of recommendations – many of which felt a little overwhelming at the time but the one that he stressed to me that was of significant value was a ductless heat pump. When he saw the confused look on my face he realized that this needed further explanation. By the time he left, I found out that it was possible to get a reasonably priced heating system that would be 300-400% efficient that would also qualify for federal and provincial rebates and that it would reduce our heating bills dramatically in the winter and provide us with A/C in the summer – all without the need for a furnace or duct work.
So I did my research, pitched the idea to Al and, with tentative approval, added a ductless heat pump to our budget/project estimate.
My research on ductless (mini-split) air-source heat pumps led me all over the place. Lots of different companies are making them at a variety of price points. Like anything, the quality varies too and determining where to get the best value/bang for your buck is the tricky part. In a nut-shell, I narrowed the field down to:
At the end we chose the Mitsubishi Mr. Slim. Although all of the 4 finalists had a good and lasting reputation (in Europe and Japan, where they’ve been using these systems for decades – because they’re a few steps ahead of us in energy efficiency and use of space), and they were all priced comparably, the decision came down to preferred features of the units (size of indoor unit, noise level, programmability, max cooling, max heating, number of fan speeds, etc.) and local availability of the units. For example, no one in our city carried Fujitsu.
Hooking up the external compressor unit. A Mitsubishi MSZ-15GENA
We considered ordering the heat pump online and not through a local mechanical or HVAC company, but we soon rejected that idea. Recall now that Al’s Dutch and I’m Scottish… after noticing that the actual retail cost of the units was half the price of the quotes we were looking at, we wanted to look into just how complicated the installation process would be. Well, in the end, we hired a local company and paid them their asking price. Why? Because realistically, we could not pressurize and properly install refrigerant ourselves (nor should we, even if we thought we could in the absence of proper training) and the companies that install these units provide labour warranties and sometimes they even extend the parts warranty too if they feel confident enough in the product. We decided that these extras, together with the time saved by having others install it, would be worth the doubling in cost. We did manage to save ourselves a bit of money having Al run the electrical feed himself and by providing the concrete pad for the exterior compressor unit. As it happened, Al ended up helping with the install of the interior unit, but that’s because he wanted to make sure that it was all done to his standard.
Getting started with the hook-ups outside. The compressor is in place and lines are being run.
The pro is flaring the end of the tubing with a special tool so that he can make the connections.
The system is hooked up and is being pressurized with Nitrogen to a level well above what would be experienced with the refrigerant in the lines. The gauges here measure the pressure and allow the installer to see any changes. This test lasts over an hour. The needles did not change their positions at all (this is good).
The installer is testing his connections for leaks by spraying soapy water where connections were made. Any leaks would be indicated by bubbles at the site where air was escaping.
Here is how it looked before it got covered where the lines ran into the house. Al spray-foamed everywhere he could with the window and door foam.
The finished product outside
Inside unit getting ready for install. This is the mounting plate for the condenser unit.
The "head" is being mounted and connected to the lines coming in from outside. This ended up being a 3-man job and then they had to send a journeyman back a couple of weeks later to get the mounting a little tighter to the wall.
We are so happy with our new mini-split heat pump! At last our house is a comfortable temperature all the time. The unit is almost completely silent – both indoors and out. Both indoor and outdoor units are relatively small (one of the reasons we opted for the Mitsubishi was that its indoor unit is 10 inches narrower than the Daikin) and best of all, our electric bill is dropping like a rock!
Let’s time warp again (and pretend that I’m not writing this almost 3 months after the fact because I would never be that far behind!) and look at our most recent electricity bill after the coldest November on record here in over 50 years. The bill was HALF that of last year at this time! Now, I do realize that this isn’t all heat pump attributable… we have since replaced all of the windows, air sealed and insulated the house, but it all adds up to our bills being half of what they used to be. I know that the heat pump contributes significantly.
So how much did it cost us? All said and done, $3752 (taxes in). We are expecting $1500 in energy rebates. Once that money is received, it won’t take long after that for the heat pump to pay for itself in reduced energy bills.
To decide what size of heat pump to get we did our own estimates based on square footage of the area we wanted heated and what the companies recommend for their various units and room size. Then we had the local companies come in to do a proper measure and assessment of where the warm air would realistically flow and we came up with about the same answer. We only wanted to heat the main living level, this is 750 sqft, of which most is all open now that we’ve bashed out a bunch of walls. So to service this space we installed one 15,000 BTU outside compressor together with one “head” (inside condenser unit) centrally located in the living room, closest to the dinning room and kitchen and pointing at the office/guest room. So far it seems like a perfect match.
One of the big appealing factors in the decision to go with this unit was the electrical panel. Traditional electric heat requires considerable amperage, and a lot of circuit breaker slots in the panel. In a new house this is seldom an issue with the standard 200 amp service. In an older house like ours with a 100-amp panel, the slots need to be allocated quite carefully, particularly once the kitchen has been properly wired, and all of the other major loads, like the clothes dryer, water heater, and stove, have been satisfied. The good news about our heat pump? Because it moves heat instead of creating it, the power consumption is much lower than electric heaters of any kind. The panel requirement for our install was 240 volts, but only 15 amps. This would safely power a 2800 watt traditional heater, which would draw 12 amps, and would equate to about 10000 btu/hr. We’re getting much more than that, and for a typical amperage draw of only five to seven amps!
So if you’re looking for something like this, here are some links worth following:
To see what you might get back for a heat pump rebate in Canada see this Federal website and then follow the appropriate link in “Complimentary Regional Programs” on the right side of the main page to see if your province or territory offers additional grants/rebates:
A great website to help you decide which unit(s) would best meet your needs, go to Ductless.ca
More info at Cozy World
Canada’s Federal Government Office of Energy Efficiency document on Air Source Heat Pumps
Al and Kay's Renovation 