Carrier Infinity Heat Pumps
We’re in the last months of a home under construction. There wasn’t much flexibility in the HVAC install through our builder. I was able to convince them to upgrade the furnace to an ICP Comfortmaker g97cmn1002122A. INstalled with a 3 zone Honeywell ZD10x12tz, controlled with Aprilaire 8910 (Main floor) 8463 2nd and basement.
2 story home,
2711sq ft above grade,
unfinished basement for now
We’ve air sealed with Aerobarrier and landed an ACH50 at 0.3. I’ve posted elsewhere on here with help to do a proper heat loss calc, man-j.
It’s hard to find vendors with experience with heat pumps in this area of Calgary Alberta. I’ve only had two that responded to queries around possible dual fuel or full heat pump options. One vendor offered a Carrier Infinity 18vs. He did not do any clarifications on man-j calculations, I’ve asked clarifying questions, and all he’s been able to offer is “this will work, but your furnace and your zone system isn’t ideal, so the system will never reach full optimal performance as the heat pump won’t be controlled properly and only utilize 2 stages of the 5 it’s capable of, as a result of non-communicating with the furnace. ” I’ve used GBA to try to learn some insight on dual fuel systems, but this level of detail feels better from HVAC tech’s and others with more technical knowledge than myself and the general public.
The other vendor offered ” Have a look at Daikin systems, when your house is further along to possession, call me back so we can get into the details, although your furnace will throw us some challenges.
Firstly: any insight on the technical hiccup presented by the Infinity offering?
Secondly: New house, is it worth dumping a new furnace for a new heat pump and air handler, simply to gain the longer term return on efficiencies.
Any other perspectives to be heard? Thank you all
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Replies
I’m sorry it has been such a difficult process for you. The technology is here and affordable but there’s still much friction in this portion of electrification even when the homeowner is heavily involved. You’ll have to answer the second question for yourself. It’s a lot of money to walk away from and your builder put you in a terrible position. Financially, probably zero return but there are other considerations of course.
One positive action you can take now that the furnace is installed is wait one winter and run a fuel usage based heat loss calculation, as the contractors haven’t seemed capable of running an accurate manual J. The lower the true heat loss is, the better your heat pump options will be. You might find that furnace is too large to modulate even on design day.
At 0.3 ACH/50, your house exceeds passive house standards. Perhaps the primary focus at this point should be to ensure a proper HRV/ERV to get fresh air. A house that tight will leak so little air that if you have decent insulation almost any heat system will work well....
When I replaced my heat pump I was able to pick any model I wanted because my furnace/air handler was a high end model. I went with the 18 with the 5 speeds although in retrospect I wish I had done the green speed because I don’t have gas hooked up to the house for backup heat currently. I would think you would be fine with just about any system. Ideally you would be able to utilize the 5 speeds of the carrier but the 2 should work. I need to use a dehumidifier in the shoulder seasons, I’m not sure if having a mini split with tons of variability would solve that.
I was just asking my AC repair guy about Carrier. He hates them. Hard to get parts.
The VX18 is not the best fit, the capacity chart for it only goes down to -10C. In your climate you want something that can provide some heat down to your design temperature. The 25VNA0 (Infinity 20) would be a better choice. Still not the greatest and you would need to rely on strip heaters or your gas furnace for backup heat during cold snaps.
A proper cold climate heat pump (Mitsubishi Zuba or Daikin Sky Air RZQ) would be a better fit. With either of those, you can simply take out the furnace and simplify the install.
At this stage, none of this make financial sense unless you want to go solar and mostly energy self sufficient.