Hyper Heat Mini Splits vs Propane Furnace
Hello, I am in the process of doing a remodel on my home. Just reinsulated and vapor barriered the house which is located at 8,100ft elevation in the California mountains, Zone 6. Cold snowy winters and mild summers, might use AC 5 or so days a year if we had it, but not a necessity. Furnace would be in walk out crawlspace and ducts run through soffits to the upper level (no attic)
I cannot decide between a propane forced air furnace or two mini splits. I need supplemental heat in my living area; 400 sq ft plus 200 sq ft open loft with high ceilings. I already have a pellet stove but need some extra heat on the coldest days and would also be nice to not run the pellet stove in the fall/spring on mild days.
The second area of heating would be a downstairs bedroom/bathroom which is about 360 sq ft, bathroom has heated floors and bedroom has been heated with a portable plug in heater.
I am concerned that the furnace and ductwork will be too complicated as a DIY project and that the ductwork will be spendy and very time consuming.
My concerns about mini splits are; not being efficient enough in colder weather and snow damaging the units. Utility price is about 18c a KW and $4 a gallon propane, but the furnace with ductwork and the minisplits are about the same price in my calculation.
Any thoughts?
Thank You
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Replies
I’d go with the mini splits for the sole reason that you can make your own electricity, but you can’t make your own propane.
But also, I live in a much colder climate than you, and I stay toasty warm in the winter even without a stove.
Propane is the most expensive fuel for heating, other than resistance electric.
Propane will cost more than twice as much to operate.
Depending on cost of your propane and electricity, a mini split is typically cheaper to operate (it is around me), plus you don't have to pay for the cost of installing a propane tank.
A hyper heat mini split will have no issues heating that place in zone6. Generally for heating, you can get away with a centrally located unit especially since the 2nd floor is a loft. You might need a bit of resistance heat around the perimeter of the house if you want to close doors at night time.
Not sure if it makes sense to install a dedicated unit for the bedroom. Since it only needs to be heated 8h/day, there might not be an ROI on the additional unit.
A couple of items for snow country. Make sure the unit you get comes with a pan heater and high enough off the ground to keep snow away from it. Installing under a small roof like a carport or under a 2nd story balcony is a good spot. You always want to mount the outdoor unit either on a stand on the ground or on masonry walls to avoid transmitting noise into the house.
Thank you, noise/vibration is one of my concerns. My house has no masonry and I cannot put it anywhere near the ground as we get way too much snow.
Would the condenser be better placed on the shady side of the house under a deck or more exposed to the sun and wind on the sunny side of the house under an overhang?
Shading or wind doesn't matter much (some units have a wind guard as accessory). Important part is to allow enough airflow around the unit and keep snow away. Under a main floor deck is a bad idea as the snow berm around the perimeter can close off the airflow.
At my cottage I have the outdoor unit sitting a small cinder block platform. If you need it a couple of feet in the air, the simpler might be to install two PT posts 4"-6" away from the house and mount the outdoor unit on that. You can put a small roof on top of the posts to keep snow off and be close enough to the house that you can easily run the lines and power through the wall.
The units themselves are extremely quiet, but they still vibrate. It is this vibration that can carry if mounted on wood walls. You can have it next to a deck and not even notice it running.
Thanks again, I think my best option will be under my entry walkway which is only about 4 feet wide but 15 feet tall, protected from the wind, snowblower, etc.
Would mounting the unit to a wood wall with some kind of rubber bushing to dampen the vibration help? I would really rather avoid mounting to some posts as my house sits on a 30 degree slope and I need the unit at least 10 feet off the ground as we get crazy amounts of snow.
I am most interested in the LGred units as they are a fair price and have good cold weather performance.
I've tried mounting on wood walls and rubber isolators, it was nowhere near enough. Ended up building a ground mount under the unit, now it is silent inside.
You could probably get something to work, but you'll probably end up spending the same amount of effort as a ground mount. About the only way to make it work is to install pavers (~300lb worth) on your deck and than mount the unit on top of the pavers with proper spring isolators like these:
https://www.grainger.com/product/MASON-Floor-Mount-Vibration-Isolator-5C126
The combination of mass and good decoupling would keep the vibration out of the building. An in-between could be to try just the isolators without the pavers and only add them in if needed. Just make sure to leave enough slack in the piping.
I've had no issue with LG units. You can also search for Gree and Midea which also make excellent cold climate units.
I live at 8100 ft in the Colorado Rockies. We converted from propane forced air to minisplits 4 years ago, and it was a great improvement. The heating is much more uniform and interior humidity is much more stable in a good range (40's). Our winter time humidity used to vary down into the teens, and rarely above 30. The cost of heating is less at the current propane prices here. At first glance, our system (48K Hyper heat) looks oversize, but when it is derated for altitude (80%) and then again for 40 mph, which makes a significant impact. The old propane furnace was nominal 140K, and didn't do as well. Construction is 2X6 but the outer sheathing is not very airtight. The main mistake we made was in not splitting the system into 2 independent systems: 1 for the main floor and 1 for the walkout basement. Sometimes we need AC upstairs due to solar gain, while the basement often needs a little heat even in summer.
Thank you so much for your input. May I ask how many square feet your home is, what brand units you have, and how many wall units you have?
Our situations seems quite similar. My house has r15 between 2x4 walls, but I also have a ton of windows which I lose a ton of heat through. My main goals are to supplement the pellet stove during really cold times, to provide a thermostatically controlled system to keep the house from getting super cold when the pellet stove is not running, and to use it as the primary heating source for my downstairs bedroom.
I do not think I will ever be cooling one zone while heating the other as my solar gain is not that good except mid summer when I may use the system to cool the house slightly or during wildfire smoke when I cannot open windows.
Our house is 1250 sq ft on the main floor with same size walkout basement. The walls of the basement are about 1/3 above ground level total, mostly exposed on the walkout end. We have a Mitsubishi Hyper Heat system with one 48K compressor hooked to a branch box in the basement feeding 4 heads - 3 upstairs (18K, 12K, and 9K) and 1 in the walkout end of the basement (12K). The outdoor unit is mounted on the ground on a steel stand about 18 in high on concrete pavers, with a cedar screen structure and shed roof over. The unit is about 12 in from an exterior wall in an L formed by the garage, shielding it from the direct wind most of the time. Snow has not been a problem even with a 36 in snow, the fan exhaust keeps the immediate area clear. When the unit is running fast, there is a very mild drumming heard through the wall. I plan to turn the unit so it is along the garage wall and hopefully reduce the drumming.
In locating the outside unit, consider that while they run quietly most of the time, every now and again they undergo a defrost cycle. That involves a quite loud thunk and whoosh sound. That sound is *much* louder than the "maximum noise" in the specs. So don't locate the units near bedrooms if you can at all avoid it.
The Quick-Sling minisplit stands are designed for snow and have some additional rubber isolation stuff that helps.