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This needs far more attention. Combi boiler installers tend to massively oversize the CV. But with heat-pumps you need to be far more accurate. And it does not
by wernerb 2y ago
This needs far more attention. Combi boiler installers tend to massively oversize the CV. But with heat-pumps you need to be far more accurate. And it does not make sense to design for a temperature that occurs only a couple of days in the year. You can just have the backup heater kick in which is far more efficient for a couple of days than having a heavier heatpump for the rest of the year that can not modulate back as much as a smaller heatpump.
- stilley2 2y agoI recommend this technology connections video which dives into this in wonderful detail https://youtu.be/DTsQjiPlksA?si=gx18FGOcjsv5PpNg https://youtu.be/DTsQjiPlksA?si=gx18FGOcjsv5PpNg
- rssoconnor 2y ago> than having a heavier heatpump for the rest of the year that can not modulate back as much as a smaller heatpump. Aren't basically all modern heatpump variable speed, and thus can modulate back? That said, I totally agree with your overall point about right-sizing your heat pump, but it is more about saving money on the unit rather than worrying about cycle times.
- bluGill 2y agoModern heatpumps can modulate, though it isn't 100%. I recommend people consider two smaller heat pumps in many cases - it costs more upfront but can modulate down more and if one system breaks the other can handle everything most days of the year (some rooms will be a bit uncomfortable)