Heat Pump Sizing Mr. Cool Hyper or Versa Pro
Which one should I buy?
I have an 1100 sqft house that running Manual J I am coming up with 12,000 BTUs for heating and 11,000 BTUs for cooling. The low temperature rarely goes below 10 degrees F but can do that a few days a year. I am more concerned about heating capacity than cooling. I am in climate zone 5 at about 2200 feet.
I am doing a ducted system with the entire duct system in the building envelope. The building is very tight.
Sizing says get the 1.5 ton since it is the smallest but there is only a 1.5 ton in the Versa Pro. I started looking at using a 2 ton system because I have no interest in putting in a heat strip. On the low end the 1.5 at 5 degrees F is rated at 12,000 BTUs, the 2 ton is around 18,000 BTUs. The COP is better on the Hyper heat than the Versa Pro in the avg temp range.
A few questions:
Is there a reason I should go for the 2-ton compared to the 1.5 ton?
If the 2 ton makes sense, should I spend the extra money and go for the hyper heat? The hyper heat is $700 more for the system.
I am starting to wonder if I am overthinking this.
Lastly and related. I need to put in an ERV but the sizing says 35 CFM. Any suggestions for a small capacity ERV that can feed into the duct system?
Thanks
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Replies
To my ear you do not have enough very cold (< +10°F) hours to get a ROI on the extra cost for vapor injection IE hyper heat.
Oversizing is a big problem in the cooling season in hot muggy climates.
An oversized HP in the heating season will cycle on and off but the energy penalty is not that large and at 2200 feet muggy is not likely to be a problem.
Consider one advantage of under sizing is the HP will run much longer and more often at its max speed that is when the HP make the warmest air it possible can, that equals more comfort.
I know you said no to strip heat but the way I see it there are some advantages. If you HP is undersized a little and the strip heat runs for the coldest 10% how many hours would that be a year for my house it is very few and they are the hours when the HP COP is at its lowest most likely under 2. Sound like less than a 10% more fuel. The other advantage is when the HP goes down and it will from time to time with out the strips it is a full blown emergency and with the strips it is only a budget issue that the fuel costs are 4 time higher or so. Sounds bad but the last time my HP was down waiting for a call and then the part to arrive I was out $1.75 a day. Yes, it bugged me but it is not a real problem. Another thing is the installer is unlikely to push for the 4 ton HP he always put in a house the size of yours if you let him install oversized strip heat. The cost to run 50K of strip heat for one minute is the same as 5K for 10 minutes for the same number of BTUs. The only real cost for oversized strips is some wire and maybe a circuit breaker.
Walta
Thanks. No strip heat is because for the few days a year if needed I can run a space heater. Mostly it would be at night. The house will also have a wood stove, more for aesthetics than heat but it will toast up the house.
The not using Hyper-heat makes sense.
The cost of the electricity isn't as much the concern as just making the right investment upfront. In the next year the house will have a solar and wind system added.
I regret not getting hyperheat even in Seattle. A $700 difference would not deter me.
Thanks - I was comparing the COP on them and they are better overall in the mid heating temperatures.
Space heater are crazy dangerous and a poor plan.
The US Department of Energy records about 25,000 house fires every year that are linked to a space heater fire. Many result in trips to the emergency room, with more than 300 fatalities each year.
Walta
Each room in the house has a dedicated 20 amp circuit and outlet. I currently have wall mount heaters in the house because I have been waiting for the federal rebates to come in to play to add to the 30% tax credit for the heat pump.
I am still considering a heat strip and if I want to run another circuit for it. Not a cost issue just the utility of running that for what likely would be less than a few days a year based on climate history.
Generally, but not always, the hyper heat units are more efficient overall than the non hyper heat
Generally, but not always, the larger the unit the higher the minimum turndown
The actual cost of the unit is a fraction of the installed cost, so I would suggest go with the best unit you can fit in the budget
I can afford the cost difference. I am self installing. My concern is on sizing with it being a 2 Ton. Thanks for the input.
In the winter oversizing only costs you money
In the summer it can be less comfortable, again, depending on turn down and actual load.
If you get a polar vortex and the house drops to 62 degrees, is it the end of the world?
Even though it won't save money overall, I'd still oversize to avoid the heat strip if possible. I think we're about a decade away from having a real problem with winter peak electricity demand, and strip heat makes it much worse. It's a societal problem, not an individual problem, so you probably won't see the benefit yourself, but you can feel good about it.
It's fine to install the strip heat. Just ideal if you don't need it on the coldest day of the year.
The oversizing would be to the 2-ton Versa Pro because of the extra BTU at 5 degrees.
I am planning on avoiding the electricity controls coming by installing solar and wind along with storage.
Thanks.
@ronnie2b - Any chance you looked at the BlueRidge 1.5T (AHRI#208101242)? BlueRidge sells a 2T heat pump (#208101243) with the exact same specs as the MrCool HyperHeat 2T (#211497151), but then also offers it in a 1.5T unit in this line and AHRI spec shows better low temp performance than the MrCool. Does require flare line set connections.
Seems like these are all Midea units inside and can also be found as ACIQ, Senville, C&H. Very difficult to know what is what. Like you said, am I overthinking this? Very similar requirements here in Cincinnati. Any advice is appreciated!