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And said they would also fit a Air source heat pump system just wondering does they mean they fit radiators in each room and fit ba new water tank?
I hope it does my house has no heating apart from plug in heaters and my water tank has a leak.
Not got one myself but some of this might be useful for you.
If the installers are doing internal wall insulation this will be between 50 mm and 100 mm thick so your rooms could become 4" to 8" smaller. External wall insulation tends to be less disruptive but might not be suited to some properties.
ASHP tend to deliver water at about 45°C for radiators or about 35°C for underfloor heating. Traditional boiler systems have distribution temperatures in excess of 65°C. To be able to deliver heat at an appropriate rate the emitter surface area needs to increase so they will either fit oversized radiators or use an underfloor system (thin plastic hot water pipes running under the whole of the floor, either under a wooden subfloor or within a concrete screed).
The underfloor option is a lot more work as all of the floor coverings would need to come up and the bottoms of all your doors cut down. Underfloor is more likely to be done new build while radiators are more likely to be used in a retrofit. It is worth asking so you will know what to expect in terms of disruption/clearing rooms.
ASHP don't have the power to provide hot water on demand so you will definitely have a hot water cylinder which might include an electric immersion heater so that the system can be brought up to 60°C periodically to kill off legionella bacteria which can arise in a low temperature heating system.
The main problems people seem to get with heat pumps are due to incorrect sizing and more complicated controllers.
The company should have to do proper heat loss calculations based on the level of insulation that will be achieved and this will determine the capacity of the heat pump. If they get it wrong or the people doing the insulation have cut corners it might not work as expected. If a heat pump is too big it will cycle excessively, cost more and wear out more quickly than it should, if it is too small it won't be able warm the place up on colder days. If the heat pump being made to work too hard (e.g. because it is undersized) you will see a build up of ice on the fins of the outside unit. Most units will have an auto defrost cycle which in some cases is a direct electric heater, while others can run in reverse and suck a bit of heat out of the house.
Control systems for heat pumps can be complicated, user unfriendly or just poorly explained to end users. Many folk are used to putting the heating on when they feel cold and a high temperature boiler system will bring the place up to temperature reasonably quickly. Because the ASHP runs at lower temperatures it can take longer to bring the temperature up so the timer/thermostat might need to be allowed to come on earlier. It is often said that a heat pump is better a providing steady low level heat rather than a quick boost.
If you are currently using plug in electric/storage type heaters the heat pump should use at least three times less electricity to deliver the same amount of heat (even less if the insulation is done well).
Good luck with it, ask the installers loads of questions and hopefully you will have a warmer, cheaper winter.
