Thanks for that, exactly the kind of information I was looking for, and to which I can relate. I don’t suppose perchance anyone has done the calculations on now much a heat pump of that capacity would cost to run per hour ?
Assume COP of 3 (could be up to 5 but 3 is a good ballpark figure) so 15kW will “cost” you 5kW of electricity. Most houses won’t need 15kW continuously though.
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You know what sort of fuel you use for heating now and how much you spend on it each year. So you should be able to convert that to kWh using the various standard conversions/boiler efficiency, etc.?
Taking that total annual kWh heating value then, as a heat pump will give you a coefficient of performance (COP) of 3 as ballpark figure, you can calculate your likely heating bill using electricity as for every 1kWh you put in you will get 3kWh out.
Hello All,
My apologies for not being more involved although I have seen that there are a lot of comments. We have been travelling from Lancaster to the south of France and it hasn’t seemed sensible to try to answer on my mobile. I will now go through everything and add my own comments/questions, etc.
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Yes a diversity but I see that as a water management issue more than heat pump technology issue.
Certainly not, if its underfloor heating the thermal mass will need just topping up. I had some old calculations somwhere
Our house in Hérault is an 1860 house originally built by a wine-grower. We have no land at all outside the walls so air-based heat-pumps would be a bit challenging. We have thick walls and three floors. The street-level garage occupies about 100 sq.m and has the well in a back corner. The second floor is bedrooms and bathrooms, the top is a 75 sq.m. séjour and an open terrasse. Current heating is several electric radiators and a wood burner in the séjour. We plan to cover our south-facing roof with solar PV units. We don’t need heating for much of the year and only want one moderately sized radiator on the middle floor. This is more or less above the well below. Hence the interest in a water-based heat-pump system. It is clear from all your expertise that I need more info first about what lies at the bottom of the well, whether it refills from a local source and whether it has a flow or not.
Air source units don’t have to be outside - they just need airflow (quite a lot of it though) so a cellar or attic could be do-able depening on local conditions. Wall mounting might also be possible for modern units.
Only sensible space is in the garage which would have to have an air supply, probably through a window. Otherwise the terrasse or, with permission, overhanging next door’s roof or the street (we live in a small impasse). But the water in the well might be available so what’s not to lose? Others complain about the noise of air-source pumps.
Call in a specialist company for a survey but I doubt a single well would be sufficient.
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I think you may be right on both counts. I will do that when we are closer to moving finally. Thanks to all for the hints.
If it is a well in a house, I doubt it has much water flow. When originally installed it probably only served a family so they’d only take a few buckets of water a day from it and it would then refill over the day. The depth could also change significantly with the time of year as the water table level changes. I once had a cellar in England which flooded to a few inches in summer but was dry in winter.
Just get a pump and extract a good volume of water. You’d then be able to gauge how quickly it filled and thus flow.