In late 2018, we installed a mini-split heat pump for the purpose of reducing our electricity bill. Around here in the most easterly parts of Canada, most of the houses use electric baseboard heating as the primary source of heating.
While baseboard heating is a lower cost option during installation, the operating costs can rack up quickly during the colder winter months. Combine this with rising electricity rates (cough.. Muskrat Falls.. cough), a 3,000 sq ft house can face winter heating bills from $600 to $1,000/month.
What is a Mini-Split Heat Pump?
Before I get into the merits of a mini-split – what exactly is it? It’s essentially a heat pump that has an outside unit and an inside register (like the picture above) that’s usually on an exterior wall.
In the winter, the units will extract any warmth in the air (will be less efficient the colder it gets), and expel it the inside of your home. In the summer, the AC will extract heat (and moisture) from the inside of your home and expel outside (while also blowing cold air inside). From my research and talking to people with mini-splits, the energy savings works out to be between 15%-35%
The beauty of mini-splits is that you do not need additional ductwork, but the downside is that it’s only meant to heat one space/room per unit. The ideal situation for a mini-split is an open concept area that is used as the main area in the house. Oh, and you’ll also need to wrap your head around the size of the inside register. Some of the biggest concerns are the “look” of the unit, which turns out to be not that big of a deal (at least to me!).
In early 2019, I posted the results in having a mini-split installed for the first few months of the year. The results were promising, but it only gave details of the initial progress.
One gap in the initial findings is that it didn’t include summer months. A typical house in NL does not have air conditioning due to practicality, so the energy usage is typically lower during the summer.
One of the major benefits of a mini-split is that is has a split personality. In the winter, it can provide efficient heat, and in the summer, it can provide air conditioning. While summer in NL is not exactly heat-wave caliber, the humidity can get stuffy at times in which an air conditioner would provide some comfort.
We did find that we used the air conditioning feature for a handful of days during July, but nothing like using the heat option during the winter which is on 24/7.
Now with a full year’s worth of data, let’s take a look to see if the savings rates kept up to the initial findings.
Energy Usage Comparison – Electric Heat vs Mini-Split
|Date||Electric (kWh)||Temperature Diff||Normalized Electric (kWh)||Date||Mini Split (kWh)||Difference||Savings %|
|Sep 2017||915||0||915||Sep 2018||1048||-133||-14.54%|
|Oct 2017||1132||0.035||1171.62||Oct 2018||1096||75.62||6.45%|
|Nov 2017||1881||0.105||2078.505||Nov 2018||1443||635.505||30.58%|
|Dec 2017||2787||0.14||3177.18||Dec 2018||1903||1274.18||40.10%|
|Jan 2018||2548||0.105||2815.54||Jan 2019||1784||1031.54||36.64%|
|Feb 2018||2489||0.245||3098.805||Feb 2019||1864||1234.805||39.85%|
|Mar 2018||2525||0||2525||Mar 2019||1567||958||37.94%|
|Apr 2018||1883||0.14||2146.62||Apr 2019||1303||843.62||39.30%|
|May 2018||1567||0||1567||May 2019||1145||422||26.93%|
|Jun 2018||1325||0||1325||Jun 2019||917||408||30.79%|
|Jul 2018||798||0||798||Jul 2019||825||-27||-3.38%|
|Aug 2018||923||0||923||Aug 2019||714||209||22.64%|
As you can see from the numbers above, energy savings really becomes apparent during the winter months. The savings from December to April was in the 40% range, which is offset a little AC energy usage in the summer months.
In dollar value, a 6900 kWh savings equates to about $900 with an electricity rate of $0.133/kWh. The higher the rates, the higher the savings (as can be seen by the table below).
Cost of Electric vs. Mini Split Usage
|Price per kWh||Electric (kWh)||Normalized Electric (kWh)||Mini Split (kWh)||Difference|
In terms of pay off, I’ve calculated that the unit should pay for itself between 5-6 years. If rates jump to $0.17/kWh like many are expecting, then pay off is between 4-5 years.
Note that not all mini-split installations will result in significant savings. It is important to make sure that your house is properly insulated, at least up to code (R50 attic installation in NL). More details in the original article.
Next, the location of the interior register is important. You want the air blowing out to replace as many electric baseboard heaters as possible. It turns out that the design of our house is ideal where the register can heat the main area of the house, but also blow out to the main foyer where it can heat the kid’s bedrooms at night.
The mini-split in our house replaces all of the heaters in the main area (family room + kitchen+living room), the foyer, and the kid’s bedrooms. As baseboard heaters use about 225W/ft of energy, the mini-split replaced more than 6,000W worth of baseboard heaters.
But also note that we often close off the living room, and certainly close off as many rooms as possible on the main floor during the night to maximize the heat flowing upstairs.
As mentioned above, the savings from installing a mini-split will depend entirely on the number of baseboard heaters that you replace. For us, we replaced at between 25-30 ft worth of electric baseboard heaters (~6kw) with a single mini-split running at less than 1.2kW. The cherry on top is that the house is more comfortable.
If you live in Eastern Canada, especially if you live in NL with the prospects of rising electricity rates, I would highly recommend a reputable and branded mini-split heat pump. However, before making the investments into a mini-split, I would recommend that you check to see if your insulation is up to code. Insulate first, then work on efficient heat sources.
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