Are ASHP the way to go?

Mstty

Spoonie_Turtle said:

Mstty said:

Spoonie_Turtle said:

Mstty said:

I would suggest going for a named brand that has been in the ASHP market for a long time.

And make sure to go for a model that doesn't have an expensive standby consumption.

Probably a good time to start a list of "high resting standby consumption makes and models"

I can say our Mitsubishi Ecodan 8.5kwh was on all summer heating the water 4 times a week and does not have a vampire load...thankfully.

Ours is also Ecodan, PUHZ-W85VAA (does that mean it's 8.5kW?).

A screenshot of one site I found says the PUHZ- is the R410 model, whereas PUZ- is the R32 model.  Unfortunately my tablet didn't do its clever thing of linking to the website - I think I took a screenshot of that because the R32 models didn't have a vampire load whereas ours (an R410) does, but I can't be 100% certain, the context is slightly unclear.

I do not know what the different models mean, either, but the terms are there for anyone wanting to investigate.

I think technically they are 8.5-9kwh models from what I have read in the tech spec manual when I need to get to sleep quickly. Looks like we are R410a as well slightly different model number though.

Spoonie_Turtle

Mstty said:

Spoonie_Turtle said:

Mstty said:

Spoonie_Turtle said:

Mstty said:

I would suggest going for a named brand that has been in the ASHP market for a long time.

And make sure to go for a model that doesn't have an expensive standby consumption.

Probably a good time to start a list of "high resting standby consumption makes and models"

I can say our Mitsubishi Ecodan 8.5kwh was on all summer heating the water 4 times a week and does not have a vampire load...thankfully.

Ours is also Ecodan, PUHZ-W85VAA (does that mean it's 8.5kW?).

A screenshot of one site I found says the PUHZ- is the R410 model, whereas PUZ- is the R32 model.  Unfortunately my tablet didn't do its clever thing of linking to the website - I think I took a screenshot of that because the R32 models didn't have a vampire load whereas ours (an R410) does, but I can't be 100% certain, the context is slightly unclear.

I do not know what the different models mean, either, but the terms are there for anyone wanting to investigate.

I think technically they are 8.5-9kwh models from what I have read in the tech spec manual when I need to get to sleep quickly. Looks like we are R410a as well slightly different model number though.

Yes our label looks like that too, I don't understand the different specs in one model but I don't think I really need to know.

It has *just* dawned on me, you saying yours is type R410A - our label says that too!  So I was slightly wrong about that, and it doesn't help rule anything out except perhaps just our particular model *sigh*

Reed_Richards

The most economical way to run a heat pump is to make the temperature difference between the outside air and whatever it is heating as small as possible.  So an air-to-air heat pump only has to heat the air to room temperature whereas an air-to-water heat pump has to heat the water to some way above room temperature in order to heat the room.  Underfloor Heating (UFH) generally requires a modest water temperature, no more than 40 C.  Radiators may need a higher temperature unless they have a very large surface area.  Therefore if you mix UFH and radiators you may lose the economic benefits of your UFH.  You might want a heat pump that reduces it's output flow temperature when only the UFH is demanding heat; some heat pumps can do this, mine cannot.  Or you make the surface area of your radiators so huge that they can run at the same water temperature as your UFH.

Mstty

Spoonie_Turtle said:

Mstty said:

Spoonie_Turtle said:

Mstty said:

Spoonie_Turtle said:

Mstty said:

I would suggest going for a named brand that has been in the ASHP market for a long time.

And make sure to go for a model that doesn't have an expensive standby consumption.

Probably a good time to start a list of "high resting standby consumption makes and models"

I can say our Mitsubishi Ecodan 8.5kwh was on all summer heating the water 4 times a week and does not have a vampire load...thankfully.

Ours is also Ecodan, PUHZ-W85VAA (does that mean it's 8.5kW?).

A screenshot of one site I found says the PUHZ- is the R410 model, whereas PUZ- is the R32 model.  Unfortunately my tablet didn't do its clever thing of linking to the website - I think I took a screenshot of that because the R32 models didn't have a vampire load whereas ours (an R410) does, but I can't be 100% certain, the context is slightly unclear.

I do not know what the different models mean, either, but the terms are there for anyone wanting to investigate.

I think technically they are 8.5-9kwh models from what I have read in the tech spec manual when I need to get to sleep quickly. Looks like we are R410a as well slightly different model number though.

Yes our label looks like that too, I don't understand the different specs in one model but I don't think I really need to know.

It has *just* dawned on me, you saying yours is type R410A - our label says that too!  So I was slightly wrong about that, and it doesn't help rule anything out except perhaps just our particular model *sigh*

Ours will be a 2015 model maybe yours is a later date?

Also can't rule out different install and setup.

matt_drummer

Spoonie_Turtle said:

Mstty said:

Spoonie_Turtle said:

Mstty said:

Spoonie_Turtle said:

Mstty said:

I would suggest going for a named brand that has been in the ASHP market for a long time.

And make sure to go for a model that doesn't have an expensive standby consumption.

Probably a good time to start a list of "high resting standby consumption makes and models"

I can say our Mitsubishi Ecodan 8.5kwh was on all summer heating the water 4 times a week and does not have a vampire load...thankfully.

Ours is also Ecodan, PUHZ-W85VAA (does that mean it's 8.5kW?).

A screenshot of one site I found says the PUHZ- is the R410 model, whereas PUZ- is the R32 model.  Unfortunately my tablet didn't do its clever thing of linking to the website - I think I took a screenshot of that because the R32 models didn't have a vampire load whereas ours (an R410) does, but I can't be 100% certain, the context is slightly unclear.

I do not know what the different models mean, either, but the terms are there for anyone wanting to investigate.

I think technically they are 8.5-9kwh models from what I have read in the tech spec manual when I need to get to sleep quickly. Looks like we are R410a as well slightly different model number though.

Yes our label looks like that too, I don't understand the different specs in one model but I don't think I really need to know.

It has *just* dawned on me, you saying yours is type R410A - our label says that too!  So I was slightly wrong about that, and it doesn't help rule anything out except perhaps just our particular model *sigh*

It's the specification of two different models, an 8.5 Kw and a 9.0 Kw.

It looks like yours is an 8.5 Kw model so the table on the left applies to you heat pump.

Unless anybody knows any different?

ProDave

I have a new build (self build) with ASHP and it works very well.  A few comments.

With UFH you want a LOT of insulation under the floor. Don't just aim for the building regs minimum, fit as much as you can physically fit and it is vital it is detailed properly so no chance of air leaks bypassing the insulation.  Someone I know calculated that if you just went for BR minimum insulation then 8% of the heat would be wasted down to the sub floor.

Fit UFH upstairs as well, or massive over sized radiators, ASHP's work better at lower temperatures.

Avoid the "heat pump" specialists, they are the ones that seem to magic up the expensive quotes.  Go back to basics, an ASHP works like a system boiler, it heats water, that is it.  It sits outside so treat it like an outdoor boiler.  Now you have established that, any plumber that can plumb an S plan heating system with a system boiler can plumb a heating system with an ASHP.  The plumbing aspect should not cost any different to plumbing an outdoor system boiler.  There is perhaps 2 days work for a sparky, the electrics for an ASHP are a little more complicated than a system boiler.

You can buy an ASHP for not much more than £3K  So only a little more than a gas boiler.

You can see what I am saying, it should not be much more expensive to fit than gas.

Spoonie_Turtle

Mstty said:

Spoonie_Turtle said:

Mstty said:

Spoonie_Turtle said:

Mstty said:

Spoonie_Turtle said:

Mstty said:

I would suggest going for a named brand that has been in the ASHP market for a long time.

And make sure to go for a model that doesn't have an expensive standby consumption.

Probably a good time to start a list of "high resting standby consumption makes and models"

I can say our Mitsubishi Ecodan 8.5kwh was on all summer heating the water 4 times a week and does not have a vampire load...thankfully.

Ours is also Ecodan, PUHZ-W85VAA (does that mean it's 8.5kW?).

A screenshot of one site I found says the PUHZ- is the R410 model, whereas PUZ- is the R32 model.  Unfortunately my tablet didn't do its clever thing of linking to the website - I think I took a screenshot of that because the R32 models didn't have a vampire load whereas ours (an R410) does, but I can't be 100% certain, the context is slightly unclear.

I do not know what the different models mean, either, but the terms are there for anyone wanting to investigate.

I think technically they are 8.5-9kwh models from what I have read in the tech spec manual when I need to get to sleep quickly. Looks like we are R410a as well slightly different model number though.

Yes our label looks like that too, I don't understand the different specs in one model but I don't think I really need to know.

It has *just* dawned on me, you saying yours is type R410A - our label says that too!  So I was slightly wrong about that, and it doesn't help rule anything out except perhaps just our particular model *sigh*

Ours will be a 2015 model maybe yours is a later date?

Also can't rule out different install and setup.

2019.
Yeah, I don't know if we'll ever really know to be honest.

gazb_2

ProDave said:

I have a new build (self build) with ASHP and it works very well.  A few comments.

With UFH you want a LOT of insulation under the floor. Don't just aim for the building regs minimum, fit as much as you can physically fit and it is vital it is detailed properly so no chance of air leaks bypassing the insulation.  Someone I know calculated that if you just went for BR minimum insulation then 8% of the heat would be wasted down to the sub floor.

Fit UFH upstairs as well, or massive over sized radiators, ASHP's work better at lower temperatures.

Avoid the "heat pump" specialists, they are the ones that seem to magic up the expensive quotes.  Go back to basics, an ASHP works like a system boiler, it heats water, that is it.  It sits outside so treat it like an outdoor boiler.  Now you have established that, any plumber that can plumb an S plan heating system with a system boiler can plumb a heating system with an ASHP.  The plumbing aspect should not cost any different to plumbing an outdoor system boiler.  There is perhaps 2 days work for a sparky, the electrics for an ASHP are a little more complicated than a system boiler.

You can buy an ASHP for not much more than £3K  So only a little more than a gas boiler.

You can see what I am saying, it should not be much more expensive to fit than gas.

That’s what I though. I’m a self employed carpenter. I asked the plumber on the job this morning about cost difference when starting from scratch between a gas boiler and air source. He said the same as you, little difference, plus you get the government grant too

ProDave

The grant requires you to use an MCS registered company and then you are suddenly back to inflated prices, arguably you don't benefit from the grant, the installer does.

matt_drummer

ProDave said:

The grant requires you to use an MCS registered company and then you are suddenly back to inflated prices, arguably you don't benefit from the grant, the installer does.

Where do you buy an air source heat pump and all the stuff to go with it for £3,000?

This is my reference

Midsummer Wholesale

And if it is not done by an MCS registered installer those prices are plus VAT at 20%

I would think that a 7Kw Vaillant heat pump and tank would cost at least £6,000 plus VAT and then theres all the other stuff you would need like pipes, fittings and electrical stuff.

It soon adds up!