Air Source Heat Pump

[not done it yet]

Because people don't understand that a well insulated house doesn't require 55c+ rads

No! Nothing to do with ‘what the rads need’. The rads should always operate at the required temperature to deliver the amount of heat required for that area. The system is specced with that constraint. You ain’t going to get hot water (at 55 degrees) from that system, at that temperature, at its ’rated‘ output. Simple as that.

Not many read and/or understand the ratings - and so rely on know-all (but often ‘no-nothing’) salespersons who are there to get a sale as their main objective (sales are money in their pockets!), so sell the most expensive kit they think the customer can afford - but which may not perform up to the expectations of that customer.

 

[Wildefalcon]

I think the discussion captures the key points nicely:

Existing houses are very badly built, in general, and that stops heat pumps being a viable option for most.

As ever, follow the money, who benefits from poor housing?

So the "con' is suggesting heat pumps work for badly insulated and sealed properties designed to consume oil, has and coal at fossil fuel shareholder acceptable rates.

I'll keep burning logs, I'll cut a tree every few years, job done.

 

[slim_boy_fat]

Nobody around here can understand how he got away with erecting them

Brown envelopes? *cough... cough*

 

[Mikes]

Yes, unfortunately manufacturers do not often state UK design conditions as the first piece of information. This is common for most manufacturers manufacturing refrigeration cooling or heating products and was meant to make it easy to compare like for like performance.
I would say that if your house is well constructed both thermally and air tightness then the output would be just about right. Unfortunately as stated the output is less due to the derating of the unit at lower ambients. I would ask Grant for the units output at -1 C and -4 C so that you can make an informed judgement based on fact.
You say that the unit never freezes up so I would also check (might have to be by observation) that it does not stay in defrost mode for too long which obviously has a detrimental effect on the output. You can get a cheap clamp on thermometer which you could put on a suitable piece of the flow pipework from the unit (before any take-offs) and then be able to tell what the actual temp is. Whilst the underfloor heating may still give enough output at a reduced temperature flow as generally they install more pipework than actually needed to give coverage across the floor, the radiator output fall dramatically as the flow temperature drops. The output from a radiator is based on the mean temperature (between flow and return) minus the room temperature. If you look at a radiator selection chart they give the output at varying conditions and also correction factors so you can see how the performance drops.
If you do decide to instal an auxiliary electric boiler be very careful to ensure that it is controlled to never exceed the maximum return water temperature that the heat pump can accept as this would cause problems with the refrigerant.

 

[Blobber]

This is the future you know it makes sense! it like most modern stuff sold to us as being the best thing ever but its all badly installed, badly specked rubbish with bad after sales!

 

[Blobber]

Either.

I think some genuine research was done and it was noted 15 cats in a wall mounted cage should heat up the average living room.

I wonder how many KW 8 standard poodles put out?

 

[dobbslc]

About the same as the cats but if you cross breed the Poddles into Labradodles the extra heat from wagging tails is worth at least 5 extra cats.
It's complicated!

 

[Shox Dr]

About the same as the cats but if you cross breed the Poddles into Labradodles the extra heat from wagging tails is worth at least 5 extra cats.
It's complicated!

Joking apart. Ive never been cold in a Pig stye or coo shed, its no wonder farmers the sleep above their stock. Maybe we need to start it again. Couple of Pigs and a Goat for what the Pigs wont eat. Happy days.

As for heat pumps I thought they were only good for underfloor heating as a back ground heat. With supplement heating (Rads) from another source when required.

 

[striker]

My cousin put in the ground heat source system when he built his house. It works really well but the pump has a very large motor that eats electricity. He knew this & was going to erect a small windmill to offset the electricity costs. But when he went for full planning permission for the windmill he was refused, even though they had said yes at first. He lives in the middle of nowhere with no near neighbours so no clear reason for refusal!

So he is now stuck with a big electricity bill until the planners get sense & permit the windmill!

In a remote location I'd be inclined to just put a small wind turbine up.
I tend to go with "better to ask forgiveness than seek permission" for most things!

 

[Onoff]

My oil boiler is set I think at 65degC. It's great and nearly 90% efficient.

Now though it's never off, struggles to keep the rooms at anything decent. Many factors why but mainly poor/lack of insulation and losses through the building fabric.

 

[Robotstar5]

Not many read and/or understand the ratings - and so rely on know-all (but often ‘no-nothing’) salespersons who are there to get a sale as their main objective (sales are money in their pockets!), so sell the most expensive kit they think the customer can afford - but which may not perform up to the expectations of that customer.

I had a good example of that when we were looking at replacing the central heating system, had quotes from a couple of heating companies who told me what size boiler I would need and what size rads would go in each room, as I'd seen British Gas advertising boiler installs I thought I'd get a quote from them, the salesman sits there with his laptop working it all out and I asked what size rads would be fitted in each room, he just said "what size do you want?" they came out 30% higher than other quotes so didn't get the job anyway.

 

[addjunkie]

Joking apart. Ive never been cold in a Pig stye or coo shed, its no wonder farmers the sleep above their stock. Maybe we need to start it again. Couple of Pigs and a Goat for what the Pigs wont eat. Happy days.

As for heat pumps I thought they were only good for underfloor heating as a back ground heat. With supplement heating (Rads) from another source when required.

Back in the days of the Bastle house and Border Reivers thats how folk heated their house as well as protected their stock. Deep littering the floor also adds to the heat as its composting while the stock is adding poo to it.

 

[Cobbler]

I had a good example of that when we were looking at replacing the central heating system, had quotes from a couple of heating companies who told me what size boiler I would need and what size rads would go in each room, as I'd seen British Gas advertising boiler installs I thought I'd get a quote from them, the salesman sits there with his laptop working it all out and I asked what size rads would be fitted in each room, he just said "what size do you want?" they came out 30% higher than other quotes so didn't get the job anyway.

My friends brother had British Gas ring up “can we give you a quote for central heating” man came out & spent most of the day measuring up & sizing rads etc, than said “where does your gas come in” ”we haven’t got gas”
”no problem, we can get it sorted””there’s no gas in the village, nearest gas is 3 miles away” gas man went ape, why didn’t you say sort of thing. Mate‘s brother’s argument was for all he knew, there must be plans to lay gas, or else why would BG be contacting him. Away goes one very upset gas man, on his mobile giving the sales team hell

 

[slim_boy_fat]

Back in the days of the Bastle house and Border Reivers thats how folk heated their house as well as protected their stock. Deep littering the floor also adds to the heat as its composting while the stock is adding poo to it.

But folk didn't smoke so much back then (if at all) - think of all the methane collecting underneath the floors.

 

[CompoSimmonite]

Joking apart. Ive never been cold in a Pig stye or coo shed, its no wonder farmers the sleep above their stock.

I believe the digestive system of a sheep causes it to emit around 1kw of heat.

 

[addjunkie]

But folk didn't smoke so much back then (if at all) - think of all the methane collecting underneath the floors.

True but no windows and slits allowing air movment would deal with that!

 

[voipio]

Air source heat pumps can have COPs of 3 or even 4, when the outside air is relatively warm. In the image of the ratings plate of the ASHP in question, the COP is given as 2.66, at an air temp of 7 deg C, and water temp 55 deg C, suggesting that the slide down the COP scale, as air temp falls, is well and truly on the way, and might well be somewhat less than 2 when the air temp is 0 deg C, so it might start to struggle to deliver anywhere near 9kW into the water flow.

 

[dyno-tron]

I have a suspicion that the over riding issue here is that air source heat pumps are generally cr@p when the outside temps are zero, or thereabouts.
I read the below or similar time and time again on t'internet.
View attachment 376273

Not quite the same setup but we had a simple wall mount AC “cool and heat” in our conservatory (outside heat exchanger). Heat mode was rated at 6kw output, don’t know if it actually gave out 6kw but it worked really well even down to -10 outside. Shorts & t-shirt in the conservatory:-)

Basically what I’m saying is that they do work in really cold weather but this was 6kw rating and only heating the conservatory (16sq/m), not the whole house.

 

[RaceDiagnostics]

And how much power was it taking to do that?

 

[DAPPH]

Im confused, do you burn the rabbits/hamsters or cuddle them?

Seeing you're confused perhaps it's better you don't go down that route , leave it to those that aren't confused .

I think the discussion captures the key points nicely:

Existing houses are very badly built, in general, and that stops heat pumps being a viable option for most.

As ever, follow the money, who benefits from poor housing?

So the "con' is suggesting heat pumps work for badly insulated and sealed properties designed to consume oil, has and coal at fossil fuel shareholder acceptable rates.

I'll keep burning logs, I'll cut a tree every few years, job done.

Either.

I think some genuine research was done and it was noted 15 cats in a wall mounted cage should heat up the average living room.

Two legged in high heels or four legged ones with furry coats