How efficient are our minisplit heat pumps in the winter

Gauging the efficiency of our heat pumps using a temperature model for our house that I established last winter when we were still heating mostly electrically. This allows me to work out the effective coefficient of performance.

[venenareligioest]

“I’ve got couple of temperature sensors” of course you have Matthias, we wouldn’t expect anything less 😂

[ZrubekFamily]

Build a cover for those outside units to keep the snow away, should help a lot.

[anttitiilikainen]

In Finland covers or canopys for air pumps outside units are rather typical, those would prevent snow issues. Would assume that depending on model they would somehow impact to air flow also, but guessing they would have minor impact. They also hide the ugly white plastic, which seems to be only option by many producers. Considering to make one with homemade bandsaw?

[TheCrimsonFlash]

We have 7 mini splits with two condensers at our house. Installed them 3 years ago. They work fantastic, even when it gets very cold outside. A lot cheaper than our old baseboard heaters, plus we get air conditioning in the summer.

[crfuzz]

I installed a DIY 18K unit over the summer (primarily for AC). I've been quite impressed at the offset it's produced to the oil boiler, especially in the shoulder season. Rough math so far has me saving half my annual fuel oil usage, with a modest increase in electrical usage. Fuel oil is around 5$/gal, and I usually use 6-700gal/winter. It's paying for itself quickly at this rate. Would love to have the granularity of the data you collected though!

[tau]

Man you are amazing. I'm off the grid in a tinyhouse, so every Wh counts and I've been dying to know about all these things! Thanks for all the work!

On a fun note: it's crazy seeing your numbers of 80-100kWh per day, compared to my 5kWh per day D: :D

[Thesaltymaker]

Great discussion. We installed a hybrid water heater with similar function to the minisplit from a gas water heater. You’ve inspired me to start collecting a bit more data with external sensors. Of course, to proof is usually in the utility bill.

[dirtwhisperer]

Nice job with the data collection and explanation of findings. I installed 3 mini splits in my house in FL and turned off the old central air. Our electric bill went down from $400 month to $150. To say I am happy would be an understatement. I know a lot of HVAC guys don't like mini splits because they are hard to work on. Right now that is not my problem. If worst came to worst I would just install a new one because the electric is already there and the hole thru the wall.

[Vigo]

Impressive data collection. Relating the COP across the temperature range to the frequency of defrost cycles is helpful insight!

[vaskoa]

Interesting. I've always wondered what is the efficiency of those things, ... I've seen overall numbers anywhere from 2 to 5 times more efficient. Thanks for all you testing Matthias, this is very informative.

[Don-sxxv]

Great presentation brother, I live here in New Brunswick also, just installed 4, seeing how I can get the best efficiency, you were very thorough, going to check out more of your vids TY

[forerunnert]

Mini splits are amazing, we're using one since this winter. Some are better at heating than others though, COP 4 or 5 is doable for really optimized ones. Around zero C we're using the same amount of electricity of 3 dishwasher cycles per 24 hours.

[geraldhenrickson]

My 8, 000 / BTU seer 21 Pioneer split heats my 23 foot travel trailer at 8 degrees no problem. It draws a constant 400 watts to do so. Above freezing, in the 30’s it draws around 240 watts and cycles on and off. My trailer is super insulated with R15 in the walls, R23 in the ceiling. There is nothing like the luxury of good insulation and one of the more efficient mini-splits. Of course a high Seer rating and the time of purchase it a bit difficult due to the initial cost being nearly twice as much. Because my power requirements are so low in both Summer and Winter, I can run all this with solar. Note that when initially started and the Pioneer is running at maximum effort, it can draw as much as 980 watts for a short time. Thanks for the video.

[Hunter]

I love this video, I just put a minisplit in my workshop and have been thinking about doing similar tests, but it seemed like too much work. Thanks for doing the work for me :) !

[davidwx]

These things are super common in Sweden and has been for 20+ years. I use one to keep +8C in my workshop. Works great! Also common is geothermal. My borehole for the house is 250m deep.

[daniellemos]

If you have extra temperature sensors I’d recommend adding one each to a liquid and vapor tube on the coil. It should help you monitor how efficient the OD coil is performing. As long as that temperature is close to outdoor ambient then your od coil is performing well.

[JonnyDIY]

And here I just complain when my utilies go up 🤣 I love it, nice job Matthias. Looks like it was a great investment 💕👍

[TOMA]

Yeah they are great, I have mini split of that particular manufacturer Midea, I think they are more efficient because they are using inverter motors for the compressor. I'm very pleased with the mini split unit so far, they are up to the job.

[pgerry]

If snow ingestion is an issue, I would build a small shelter over the outside unit that still allowed sufficent air flow.

[FX]

Build a little lean to coming off the house to cover the outside unit. It'll help with snow ingest in winter and with direct sunlight in summer. Increased efficiency year-round.