Forums DIY Ground Source Heat Pumps Reply To: Ground Source Heat Pumps
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Heat pumps work best with / can only provide a low output temperature (50degrees max?). There’s no reason why you can’t use them with radiators, you just need bigger radiators to compensate for the lower temperature they’re running at. If you have the wallspace and the listing allows, then this may be the way forward. Same goes for condenser boilers, there’s a step improvement in efficiency by running them below a certain temperature. We’ve recently replaced our rads in a solid Victorian house like yours and did just that – We used the online calculator on with ‘worst case’ options set as our minimum size requirements. It’s also more efficient to run any heating system if the return water has lost all it’s heat – heat transfer is more efficient in the ‘boiler’ when the difference in temp is higher. Bigger rads = more chance for the water to lose it’s heat. Underfloor heating is normally used because it’s simply a massive radiator. The problem you may have with UF heating is if you have suspended timber ground floors – you then have to work out how to insulate underneath to stop the heat being sucked out the void by the wind. If you have suspended floors and are thinking of replacing them with concrete ones to facilitate UF heating…don’t – you’ll give yourself ‘rising’ damp problems.

I think it’s foolish to consider anything other than heat pumps for a ‘new’ install like this if you can afford the capital expenditure, have the physical ability to install at sensible cost, and anticipate being in the house for a long time – you’re only storing up problems for yourself when fossil fuels become restricted or expensive. Heat pumps also run on electricity which is increasingly becoming sourced from renewables.

If you do go for UF heating it’s best used to provide for ‘baseload’ because it takes so long to heat up and cool down. You still need a means of providing ‘boost’ heating (stoves / fires / electric heaters).

Word of warning – I know of someone who froze their garden and killed everything growing in it by badly speccing their heatpump setup and sucking all the heat out of it. Extra pipe and digging is relatively cheap.