Do you heat your home (or, business etc) by using a heat pump alongside ‘regular’ electric heating (ie, resistive)? Maybe, heat pump plus a few strategically-placed storage heaters? Or, heat pump plus solar pre-heating of warm-water immersion cylinder?
We’re considering a switch to a heat pump at some point (instead of current gas boiler.) However I doubt we could get the house all the way to heat-pump readiness; so, I’ve considered a hybrid approach… It’s a standard semi-detached house, good loft insulation, recent cavity-wall insulation (which seems of reasonable workmanship), underfloor insulation (Elastospray); also, 2.4kW of solar PV on the roof.
Thanks for any comments on such experiences.
If you aren’t going for the BUS grant you could keep your boiler as backup and install a heat pump into the same system. A kind of DIY hybrid system.
Apart from that I know of several people with other concoctions of “hybrid”. There are storage heaters and freestanding air to air heat pumps. Also two air to water heat pumps in the same house, one for hot water and the other for space heating. Each heat pump selected to run in its optimal range.
All the owners are happy with their solutions.
A well sized heat pump does not necessarily provide all heat requirements at all times. This is particularly true where your property is exposed to extremes of temperature. Sizing a system for extreme cases can lead to fitting a larger heat pump than is normally required, leading to higher up front costs and inefficiency in normal use. Far better to have a slightly undersized system and add extra heat when required.
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Thanks Tim, sounds fairly positive. We’d definitely be going for BUS! Think it would have to be air-to-water HP, with something in addition to aid space heating if hot water demand went up. Presumably an immersion cylinder for HP-heated water can also have a (resistive) electric element in it, for topping-up?
Unless you have a high temperature heat pump you will need an immersion heater for the anti-Legionella cycle, so all dedicated heat pump cylinders have them.
I have solar thermal too, so I would need a dual cylinder. Such things are available.
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This is a good point. An air to water heat pump cannot heat domestic hot water and space heating simultaneously, so the house will start cooling while you heat the water. The poorer your home’s heat retention the more critical this is. Hence my example above with two heat pumps, one for each.
I seem to think there is a potential grid capacity issue with this, as we will all want to top up the heat with direct electric heaters, whether storage or otherwise, all together at the same time, namely in the coldest spells of weather. So the grid has to provide much greater capacity to cope with these periods, which is a lot of cost to cope with these short periods of time. So direct electric top-up heating is a good and inexpensive strategy in the short term for individual houses but a poor strategy nationally and for the planet if more of us were to go that way. Thus my thought about this is that, in the longer term, a less carbon-expensive strategy nationally would be (perhaps counter-intuitively) for us to have bottled gas waffle heaters for those cold snaps, probably of the portable variety, which can be stored out of the way for the rest of the year, making sure that we have good enough ventilation to remove the products of their combustion for the relatively few days per year when we use them. In the meantime, however, low-capital-cost direct electric heating is an attractive alternative for our household when we have visitors, and when we don’t we will apply extra jumpers and run on the spot for a minute or so every half hour.
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This is quite true in relation to the mass installation of heat pumps but the grid capacity would still be a lot less than if everyone got resistive heating.
Yes, if everyone had purely resistive heating for all their heating needs, and no heat pumps, then a hugely bigger grid would be needed. Maybe I didn’t explain it well, but my thought is that bottled gas might be the best form of heating for us all to use to top up our slightly undersized heat pumps in the cold snaps, thus avoiding the need for the nation to have a grid large enough for us all to briefly use resistive electric heating, just for that topping up, all at the same times, namely in the cold snaps.
For the Boiler Upgrade Scheme, is a slightly undersized heat pump allowed, I wonder?
I hate to think that even medium term it is acceptable to burn anything but I get your point.
With changes to ocean currents there is a risk of loosing the Gulf Stream. We will then be subject to much more severe winters as a regular occurrence. Unfortunately the government’s plans for climate tolerance/adaptation have hardly started being considered.
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