Heat Pumps

[vacbear58]

I have noticed over the years that several people have mentioned having heat pumps to drive their central heating and, as a new central heating boiler is on the cards in the foreseeable future, I wondered if anyone could give me some advice.

It would be required for heating/hot water only, the chances of me needing air conditioning where I live are remote. My current system is a gas fired combination boiler which provides heat for radiators and "instant" hot water. I am aware that I would need a hot water storage tank which my system does not currently require. I will probably have to replace the whole heating system too and would consider underfloor heating (NOT warm air) on the ground floor.

The overall area is approximately 1000sq feet over 2 floors. I live on my own and both washing machine and dishwasher are cold fill so there is no requirement for those. I already have PV panels on the part of my roof that gets most sun so solar heating is not an option.

So, anything I need to watch out for. Any dos or don'ts?

Thanks

Al

 

[askolover]

A heat pump

is just an air conditioner running in reverse...takes heat FROM outside and moves it INSIDE...then in summer, takes heat FROM inside and sends it OUTSIDE.  We had one in my last apartment and I hated it.  The Power company says it's more efficient....for who?  Them maybe.  For me, it's gas heat and regular air conditioning.  Heat pumps last half as long here in the south typically because they run twice as much...pretty much all year long.  Our neighbor has one and you can hear it running several houses away.....it also has to be serviced constantly. Then, if you have very cold temps, you either need heat strips or a changeover model that switches to gas because the colder it is outside, the less heat there is to transfer inside, and the colder it will be in your house.  I enjoy getting a break on my electric bill during the winter...with a heat pump it would be just like running the AC in the summer.

 

[sudsmaster]

Here in California, the cheapest way to heat water in most locations is with natural gas. If you already have natural gas service, I'd say stick with it. For locations without natural gas, then electricity is used, and I understand some newer water heaters include heat pumps but I suspect they fall back on resistance heating when the weather is cold. The hot water heater with a heat pump can do double duty: since hot water is generally needed all year round, in the hot summer the heat extracted from interior air is used to heat water in the hot water tank, which increases efficiency all around.

 

Since you live in Old Blighty I suspect there won't be much double duty going on with a heat pump based system.

 

 

 

 

[ronhic]

Al,

 

We have reverse cycle airconditioning both upstairs and downstairs in our house.

 

I'd almost bet my left one that if the radiators are in average to good condition, buying a new higher efficiency boiler will be simpler, cheaper and less troublesome than replacing an established system with something new, more expensive and potentially disruptive whilst it's being done. Not to mention, if it's remotely 'new tech', who will service it when if/when it needs it?

 

At least with a boiler, virtually any gas man can sort it out.

 

[petek]

I'd stick with the tried and true simple gas boiler. You've seen ours if you remember.. that big old 58 year old monster in the basement. Well it just keeps on keeping on. Had to have a seal replaced in the pump a few months ago (not a big deal) and again the service guy said don't ever replace it with something new because I'd probably be asking for trouble with something electronic screwing up. Not until it blows up or starts leaking will it go. 

 

[washer111]

In situations where it doesn't get absurdly cold, a heatpump is more efficient. For 1kWh of electricity, you get the equivalent of 2-4kWh of heating or cooling.
Systems that need constant repairing would cause me to raise question over either the technician involved not doing a good job, or the system itself being poorly designed/installed in the first place. Even if a system runs all year round, it shouldn't need lots of service, aside from routine maintenance (an annual checkup of refrigerant pressure, for leaks, to clean condenser/evaporator and change filters).

That said, go with a new boiler. You could maybe see if a heat pump is viable for this, but they cannot heat beyond around 50-55ºC. In Australia, that is the hottest those water heaters get (So I don't understand how they meet Legionella legislation...)
A quality boiler, installed by a well-reputed technician will serve you well. There is no need to tear apart your house to install heat-pumps and other wizz-bangery when everything you need is already in place.