Gas Vs Heat pump

With all the government endorsed scaremongering of the gas industry, we are now finding a lot of customers questioning us on the possibility of changing from gas spa heating to a heat pump. Allow me to explain a few issues with this change. Gas heating is a high output way of heating which depending on spa and heater sizing can give heat up times of between 30 minutes to a few hours. The smallest heat output gas heater on the market gives a heat output of approx. 16kw. Put into simple terms, minus heat loss through pipework and evaporation, that means that it will heat 16,000 litres 1 degree per hour or 8,000 litres 2 degrees, 4,000 4 degrees and so on. The electrical draw is pretty close to zero and the infrastructure is already there. The majority of spa owners are generally after a heat up time of less than one hour, so go more for a 50 to 100 kw heater. Spas (in a domestic setting) are generally very infrequently used, so therefore need to be heated from cold, say 15c to 38 – 40c. Depending on many variables, a 100 kw heater will heat a 2500l spa by 25 degrees in approximately 40 minutes. It will then maintain temperature for the duration of use, then gets turned off until in a few days/ next week/ whenever.

Heat pumps are a bit of a different beast. The largest single phase heat pumps are good for about 25 kw, generally after major electrical upgrades are done in terms of supply from meter on to the heater. These heaters can pull up to 20 amps, which is about half the available supply to most modern houses. All the while, taking 4 times as long to heat as the gas heater in the example above (which has an initial outlay of about 60% of the heat pump by the way). If however like most places, it is cost prohibitive for the upgrade of power supply and room taken up by a heat pump makes it impossible, you may be considering a smaller heat pump of say 12kw which can be run off a single phase 15amp supply.  The problem here is that you have now doubled the heat up time again (and the circulating pump is working the whole time as well). A lot of people then say that’s fine, we’ll leave it running at all times because we have solar pv  panels.

To me, unless you are in that spa every day, that is a false economy and that solar input could surely be put to better use elsewhere. If you are going to use it every day, then that’s great. We also supply heat pumps as well as gas heaters, so give us a call for whatever your spa and pool heating requirements are.