Air Heat Pump

yfaykya

Hi,

Just bought a house (3.6k sq f) with UFH downstairs and rads upstairs. It currently has an oil boiler (non condenser). I am trying to decide between getting an air heat pump or the condenser boiler. I have read many threads on boards where some ppl seemed happy and some said avoid (de-icing etc) with the air pumps.. Some of these threads were over 2 years old so I was looking for some maybe later feedback due to perhaps new models etc.

Thanks muchly.

Outkast_IRE

yfaykya wrote: »

Hi,

Just bought a house (3.6k sq f) with UFH downstairs and rads upstairs. It currently has an oil boiler (non condenser). I am trying to decide between getting an air heat pump or the condenser boiler. I have read many threads on boards where some ppl seemed happy and some said avoid (de-icing etc) with the air pumps.. Some of these threads were over 2 years old so I was looking for some maybe later feedback due to perhaps new models etc.

Thanks muchly.

Doesn't matter on the model I will give you a few of the main points you need to think about and perhaps seek answers to.

1. Heat pumps for space heating generally are at peak efficiency when heating water to temps of about 40 degrees roughly, this varies with models. However boiler heats to 60 degrees or more usually, your underfloor heating probably has a mixer valve to reduce its temperature down to less than 40 degrees so its not a problem, however your radiators upstairs are sized to give a certain heat output at 60 degrees.
If you now start pumping water at 40 degrees through them , they will be undersized and require a replacement/changing. You can get fan assisted rads which are designed to work with water at 40 degrees but this will be an added expense.

2. Heat pumps for space heating in my opinion are best utilized in well insulated relatively air tight homes, generally this means new build but a good retrofit can work too. fitted into less than ideal situations can lead to some pretty nasty electricity bills down the line.

3. Heat pumps must be sized pretty accurately, this can be tough to do without getting a good assessment done on your home, understanding how much heat is lost from each room will be important.

4.If any of the above sound like an issue for you just go for the condenser boiler, get it installed by someone competent who will get it running at maximum efficiency. You could also look at upgrading the heating controls in your home, or upgrading insulation, your money is much better spent there than an air-water heat pump in a retro-fit situation.

yfaykya

Thanks Outkast_IRE,
Good info. The house has a C1 cert at moment and has heating controls for pretty much every room. Seems like the condenser is probably the least riskiest option at mo.

TPM

yfaykya wrote: »

Hi,

Just bought a house (3.6k sq f) with UFH downstairs and rads upstairs. It currently has an oil boiler (non condenser). I am trying to decide between getting an air heat pump or the condenser boiler. I have read many threads on boards where some ppl seemed happy and some said avoid (de-icing etc) with the air pumps.. Some of these threads were over 2 years old so I was looking for some maybe later feedback due to perhaps new models etc.

Thanks muchly.

outcast gave very good info there

Another thing that you need to be careful of is the design of the underfloor heating system I have seen a lot of underfloor heating designed to run on oil boilers that would never run efficiently from a heat pump.

In a house with a heating system designed for a heat pump a heat pump will win on running costs every time. but on the other hand if the system isnt suitable you could end up with scary heating bills and little or no heat to go with it.

Dont get me wrong I think heat pumps are good in the right place but they can be a major investment and everything needs to be 100% for them to run efficiently.

Have you considered waiting to see what your heating costs before you replace the boiler?
If you know what it is costing to run it would help you make decisions.

yfaykya

TPM : My plan exactly :-)

I thought I would get the house thermal imaged too to check for heat loss also. That should be attacked no matter what. I noticed a patio door double glazed window pane was fogging up so I guess that means a broken seal.

Thanks.

Outkast_IRE

yfaykya wrote: »

TPM : My plan exactly :-)

I thought I would get the house thermal imaged too to check for heat loss also. That should be attacked no matter what. I noticed a patio door double glazed window pane was fogging up so I guess that means a broken seal.

Thanks.

Whats the insulation like in your house in general any idea of how the walls are insulated , or the depth of insulation in the attic ?

Usually the best investment for you money is putting it into not losing the heat first, then when your happy with all areas of that look at increased efficiencies from equipment such as boilers etc.

However changing the boiler to a condensing model and making sure its properly commissioned will have a instant impact too.