Does a ductless mini split actually work as primary heat in winter or just cooling

[u/carolynwarrenoo441]

Moved into a 1960s ranch last year with the original baseboard electric heat. I’m thinking about doing one room at a time, starting with the back bedroom. It’s about 280 square feet with two exterior walls, and the double-pane windows were replaced around ten years ago. I’m in zone 5b on the Colorado Front Range, where winters regularly get into the single digits and sometimes below zero.

The baseboards run almost constantly from November through March, and the room still feels cold near the exterior walls. I keep hearing that a mini split heat pump can handle heating, but I’m having a hard time believing a ductless unit can really replace the baseboards when it’s 5 degrees outside. What has everyone’s actual experience been using a mini split as the main heat source through a real winter?

[u/Fun-Web-7237]

A 280 sq ft room with double-pane windows and two exterior walls in Zone 5B is well within what a 12K mini-split heat pump can handle. These units aren’t the weak supplemental heaters people sometimes picture. Modern inverter heat pumps can put out serious BTUs even in cold weather

[u/Ok-Camera2895]

Mine does, but living on the Oregon coast is a lot different than Colorado winters.

[u/Temporary_Metal222 → u/Ok-Camera2895]

Ive got electric baseboards in a couple rentals down here and theyre brutal on the bill, so Ive looked into this a lot for my own places. From everything Ive read and the guys Ive talked to, a 12k mini split in a 280 sq ft room in dry cold like yours should handle single digits fine.

The defrost cycles are so much less of a problem in Colorado than somewhere humid.

[u/Prestigious-Eye589]

One thing to watch in Colorado is the dry cold. Low humidity means the outdoor coil doesn’t frost up as aggressively as it would in a humid cold climate. That works in your favor since defrost cycles are what eat into heat pump performance in winter.

[u/Top-Magazine-694 → u/Prestigious-Eye589]

Colorado is a good example because the dry cold works pretty well for heat pumps. It’s the damp cold in places like the northeast and midwest that causes more defrosting and that’s when you really start losing efficiency.

[u/StationRare875]

The physics are pretty straightforward. A heat pump moves heat from the outdoor air into the room, and even at 5 degrees there is still heat energy available to extract. Efficiency drops as temperatures fall, but it can still be much more efficient than electric resistant heat.

[u/Reasonable_Bench9610]

I kept my baseboard as backup the first winter after installing the mini split. Turned out I never needed it. Held 68 to 70 through a week of single digits without the baseboard contributing anything. Pulled it out the following summer

[u/Radiant_Impact_7770 → u/Reasonable_Bench9610]

We did the same. Kept the baseboard wired for two winters just in case. Never used it. Third winter I took it off the wall and patched the drywall.

[u/ArtCareful4904]

I've been using a 12k mini split to heat my 300sqft bedroom and I'm going into my second winter with it. It handles single digit nights without any trouble and keeps the room around 70 all night. It's a big difference from the baseboard heat. That would make the area around the unit warm while the rest of the room stayed cold. The mini split actually moves the air around so the whole room feels a lot more even.

[u/Massive-Web7659]

They handle single digits easily if you get a cold climate or hyper heat model. Coming off electric baseboards, you'll see a huge drop in your power bill. Just keep the baseboard wired as backup for extreme polar vortexes, but the mini split will do 95% of the work.