What size heat pump do you have?

[doncarlos]

Can anyone, that has a heat pump installed (preferably for under-floor heating), let me know what heat capacity (KW) it is and the size of the rooms that they’re heating? It’s been suggested that I install a 13KW heat pump in a 150m2 house even though I’m only interested in heating half that area (by about 3-4 degrees). I’ve done some (back-of-the-envelope) calculations which suggest that 13KW is overkill but I’d like to hear from people about their practical experience with domestic heat pumps.

TIA

[ribuck]

If it were me, I'd go for a smaller option, but the 13kW calculation is probably legitimate.

If you only heat half the area, the area has a higher ratio of surface area to volume (compared to heating the whole house), so it does need somewhat more than half the capacity. A smaller heat pump will only feel colder on the coldest days of the year, but the engineer's calculations must allow for that so they will err on the side of specifying a larger capacity heat pump.

I love the comfort of underfloor heating, but I have no experience of it in Tenerife (only in the UK and New Zealand).

[doncarlos]

Thanks for your reply and I understand what you’re saying with regards to the ratios. I’m assuming that one important contributor (of many) in determining the size of the pump must be the ambient temperature which, where I am, will be considerably higher than that of the UK (and certain parts of NZ) and thus would have an impact on the optimum size of the pump required. My amateur (I don't know what I'm doing) calculations suggest a pump of 5.5KW which is considerably smaller than what has been recommended. Depending on the manufacturer, there are several pump sizes between 5.5 and 13 KW. I just think that the engineer has included a factor for contingency that is probably larger than I would have expected but this may be the norm here.

[ribuck]

Also bear in mind that a lower power system will take longer to heat up when you first switch it on (eg if you've been away for a week).

In my experience in the UK, the installer was happy to install an "under-powered" system provided I agreed to take responsibility for any underperformance.

[doncarlos]

And were you happy with the way that the system functioned or is functioning?

Does you system also provide DHW?

[9PLUS]

And were you happy with the way that the system functioned or is functioning?

Does you system also provide DHW?



Is your electrical installation prepared for the running current of that heat pump?


What is the power consumption 5KW or lower?

[doncarlos]

Currently I have 13KW contracted and the installation is three phase. I'm hoping to convert to single phase and reduce the consumption.

The power consumption is 4.8KW.

[ribuck]

Doncarlos, the system that I undersized was a radiator system, not an underfloor system. I'm happy with it though.

[9PLUS]

Currently I have 13KW contracted and the installation is three phase. I'm hoping to convert to single phase and reduce the consumption.

The power consumption is 4.8KW.



It better in the majority of cases to have 63A (15KW) single phase supply than it is to have the 3 phase equivalent, unless you have a usable balance.

[doncarlos]

It better in the majority of cases to have 63A (15KW) single phase supply than it is to have the 3 phase equivalent, unless you have a usable balance.

Or unless if you have equipment that requires three phases.