ASHP for retrofit into small flat

[AliG]

We are looking at buying a 1 bed flat for our daughter at university, will be in her name. There are two that we are interested in both in the same building. One is top floor, one is mid floor. 46sq metres.

 

EPC suggests around 5000kWh of energy use a year 1500 for DHW and 3500 for space heating (4000+ for top floor)

 

The flat is around 40 years old. It has electric storage heaters, a hot water tank with immersion heater I think on e7 and an electric power shower. There appeared to maybe be a pump connected to the hot water tank, it looked like something built by Edison! It wasn't clear to me why they have a power shower if there is a hot water tank, would this possibly be a pressure issue or is it just incase there is no hot water? I have never had a power shower so don't know much about them.

 

We would refurbish the flat, new bathroom etc.  The more expensive flat has a new kitchen.

 

I was considering replacing the ancient hot water tank and power shower with an electric combi, I had one in my apartment in London and it worked well for a low user.

 

Various things spring to mind. The electric combi should have a tank so that hot water can be heated and stored at overnight prices. These appear to cost around £2000. No doubt installation would be expensive due to rerouting of pipework.

 

I was thinking that most hot water would be heated overnight, so the saving of using an ASHP to heat other water would not be worth the extra cost. You'd only save around £100 a year.

 

But when I looked at indoor ASHP hot water tanks such as this-

 

https://www.electricpoint.com/dimplex-edel-hot-water-cylinder-heat-pump-170l-edl170uk-520rf.html

 

I was shocked to see that they barely lost any more than an electric combi. Just a few hundred pounds extra.

 

I then remembered that in Scotland you can get an ASHP grant, but only for heating and hot water I believe, so if I could replace the heating also the system would be free.

 

The flats are in a conservation area and getting permission from both the council and other owners for an exterior mounted ASHP fan seems unlikely. But I found this product -

 

https://trianco.co.uk/activair-indoor-9111-9111

 

This is a ducted indoor ASHP (Not sure if I would need permission to drill a couple of 150mm holes in the wall). The small output would be fine in this case. This along with a new UVC and radiators would fully upgrade the apartment, rust in much lower bills and CO2 output and possibly not cost me anything or much at all to install due to the grant.

 

The flat has quite a large utility cupboard with an outside wall as well as a hot water tank cupboard so there is plenty of room to install things. I assume rerouting pipework won't be a deal breaker.

 

Does anyone have an experience of these systems or know of a similar indoor ASHP?

 

 

 

 

 

[JohnMo]

 

Electric combi - they are so expensive to run

 

Really what's wrong with what you have?

 

The heat pump you refer to is a fixed outlet temperature, so puts out the same temperature for DHW cylinder heating and central heating, it needs a cylinder and would need to be operated as a single zone fully open heating system if you don't install a buffer. Make sure you have a good read up of the manual before you decide, so you now what you are getting and it's limitations. You will need to check it's MCS certified?

[G and J]

35 minutes ago, AliG said:

The flats are in a conservation area and getting permission from both the council and other owners for an exterior mounted ASHP fan seems unlikely. But I found this product -

 

https://trianco.co.uk/activair-indoor-9111-9111

 

This is a ducted indoor ASHP (Not sure if I would need permission to drill a couple of 150mm holes in the wall). The small output would be fine in this case. This along with a new UVC and radiators would fully upgrade the apartment, rust in much lower bills and CO2 output and possibly not cost me anything or much at all to install due to the grant.

In none the flats I’ve ever been involved with would permission for those kind of penetrations be allowed.  
 

I looked at this unit early on, it appeared I could run everything in our house from just two 6” holes in our garage.  I believe that the flow rates needed would mean that the air speed would mean it would sound like a chip shop extractor.  Not an attractive idea.

[AliG]

2 minutes ago, JohnMo said:

Electric combi - they are so expensive to run

 

Really what's wrong with what you have?

 

Yes they are expensive, but would likely be a little cheaper than the current very old hot water tank.

 

Fair question. The hot water tank and pump appear to have been installed when the flat was built, so at 40 years old I would think it is the to replace them and it will be empty for a few months, so now is the time if it needs doing. It would also allow us to get rid of the power shower. TBH that is maybe just my bias against them.

 

Good point on MCS, it appears not when I just looked at the register, making the question moot.

 

The EPC suggests installing heat retention storage radiators. This would probably be a good idea as you could charge them up a lower prices during the night. However, they are surprisingly expensive at £6-800 a piece plus installation.

[AliG]

17 minutes ago, G and J said:

looked at this unit early on, it appeared I could run everything in our house from just two 6” holes in our garage.  I believe that the flow rates needed would mean that the air speed would mean it would sound like a chip shop extractor.  Not an attractive idea.

 

I thought I couldn't find the noise level, but I had missed it and it is indeed 50dB which is probably too loud. The Dimplex EDEL is only 36 which would be fine, but that just gets you hot water. A few companies make these, I am surprised they have not configured them for heating also.

 

You really think a 150mm penetration would be an issue, it is no different to a boiler flue. (Would need to check the deeds, but it is freehold property in Scotland so I don't think you need permission, planning would be required on the front elevation)

 

Even if I don't do anything, I did think this thread would be useful as installing ASHPs in flats is not something I have really seen discussed.

[JohnMo]

2 minutes ago, AliG said:

Yes they are expensive, but would likely be a little cheaper than the current very old hot water tank.

E7 cylinder costs about 13p per kWh to heat during E7 period. To replace cylinder with a new one will not make it more efficient. Heating on demand without E7 will be closer to 25p kWh, with E7 30p. 

 

Unvented E7, would give decent shower performance without the pump.

 

8 minutes ago, AliG said:

surprisingly expensive at £6-800 a piece plus installation

Look on gumtree, Facebook marketplace they come up often for cheap money.

[AliG]

22 minutes ago, JohnMo said:

E7 cylinder costs about 13p per kWh to heat during E7 period. To replace cylinder with a new one will not make it more efficient. Heating on demand without E7 will be closer to 25p kWh, with E7 30p. 

 

Unvented E7, would give decent shower performance without the pump.

The existing tank is an old school one covered in yellow foam, so the only saving I was thinking of was less heat loss in the tank. It looked like it was easily 200l or more. Probably would save 1-2kWh a day in heat losses. If the tank and pump need replaced anyway due to their age the choice is a new UVC or a new electric combi. Actually looking at costs, maybe a new UVC is a simpler/cheaper solution. This would also allow the power shower to be eliminated.

 

Indeed I would only get an electric combi with an integrated tank as heating hot water on demand would be very expensive. This relies on the system allowing the water temp to drop to a lower set point during the day before it kicks in to reheat it with a higher set point during the night. I believe that this should be doable.

[AliG]

Looks like I need to have a closer look at the system when we go look at the two flats again tomorrow.

 

Considering the hot water tank and apparent pump next to it, I wonder if there is a pressure issue.

 

Presumably low water pressure could limit my options.

 

I might take some pictures for people to comment on.

 

I have zoomed in on the brochures and both showers appear to be full Mira electric showers. Not clear why you would need these when there is a hot water tank.m

 

Having listened to people I am certainly leaning towards replacing the tank with a new UVC and then having just a mixer shower but I guess I could have flow or pressure issues that might make this difficult.

[SteamyTea]

Couple of things.

I had a flat when I was at college (the first time).

Wish it had been a top floor one, noise from above, below  sides and stairs was horrible.

 

What is the rest of the building like thermally?

 

I use 'old fashioned' E7 heating and hot water. Really not that bad price wise to run in my small house, and it is very reliable, and quiet.

But then I am in a much sunnier and warmer place.

[AliG]

18 minutes ago, SteamyTea said:

Wish it had been a top floor one, noise from above, below  sides and stairs was horrible.

A very good point. One of the two flats is top floor and we do have a preference for this reason. Luckily as all the flats are one bed it shouldn’t be too noisy.

 

Daughter is currently in halls and HATES sharing due to other people

never cleaning up after themselves. Many people it seems leave home without ever having done any cleaning themselves. Also person in the room next to her seems to be living on US time and constantly video calling people after midnight. However heating and hot water are free and they have underfloor heating!

 

We don’t know the thermal makeup of the building. The EPC uses assumed figures. It appears to be block built cavity construction from the mid 80s with the original double glazing which seems in surprising good condition. All the internal walls seem to be solid also. Loft has 170mm of insulation that we can top up. As it is quite small heating shouldn’t be too big an issue. My main other issue is Artex ceilings in a flat built in 1985 could have asbestos in them. I know it’s fine if left in situ but I’d remove it if it is asbestos or skim if it’s just Artex.

 

There is very little choice. Either much older places in worse condition or much more expensive newer places. Onerous stamp duty in Scotland makes me want to keep the price down. 

[SteamyTea]

14 minutes ago, AliG said:

Artex

Go and take a bit for testing.

My place is a 1987 build. Thermally quite good, and still with the original timber windows, though I have made up some secondary glazing that makes it triple glazed.

[G and J]

59 minutes ago, AliG said:

Luckily as all the flats are one bed it shouldn’t be too noisy

Then student life is very different nowadays. 

[SteamyTea]

2 minutes ago, G and J said:

Then student life is very different nowadays. 

Yes it is.

I lectured for a few years, some things student do is quite tame, other things opened my eyes quite a bit.

One thing they do, well did pre COVID/Brexit is travel a lot more.

[G and J]

1 hour ago, AliG said:

A very good point. One of the two flats is top floor and we do have a preference for this reason. Luckily as all the flats are one bed it shouldn’t be too noisy.

 

Daughter is currently in halls and HATES sharing due to other people

never cleaning up after themselves. Many people it seems leave home without ever having done any cleaning themselves. Also person in the room next to her seems to be living on US time and constantly video calling people after midnight. However heating and hot water are free and they have underfloor heating!

 

We don’t know the thermal makeup of the building. The EPC uses assumed figures. It appears to be block built cavity construction from the mid 80s with the original double glazing which seems in surprising good condition. All the internal walls seem to be solid also. Loft has 170mm of insulation that we can top up. As it is quite small heating shouldn’t be too big an issue. My main other issue is Artex ceilings in a flat built in 1985 could have asbestos in them. I know it’s fine if left in situ but I’d remove it if it is asbestos or skim if it’s just Artex.

 

There is very little choice. Either much older places in worse condition or much more expensive newer places. Onerous stamp duty in Scotland makes me want to keep the price down. 

We had a top floor flat in an old maltings.   Vented tank in cupboard heated by E7 and storage rads.  Hot water tap flow rate was pitiful as there was no head.  
 

Maybe that’s why there is a shower pump. 

[AliG]

Yes, I will run taps when I am there tomorrow to see if I can get an idea of what is going on.

 

I don't understand why there appears to be pump next to the tank and the shower is also pumped. The tank pump did look ancient in the one flat we saw last week. I'll try and get a picture of it.

 

I also noticed that the electric shower seemed to be a new addition as new pipes had been knocked through the wall to it from the cupboard behind. Maybe the tank pump gave out and this was the solution.

 

We could conceivably have six months before my daughter has to move into the place so plenty of time to do it up. It is extremely well located and I suspect that a lot of buyers wouldn't have the time or inclination to renovate so I could get my money back on the renovation as well as having a nicer place to live. There is a reason we live in a brand new house we built ourselves!

[SteamyTea]

14 minutes ago, G and J said:

Maybe that’s why there is a shower pump. 

My system is vented, and I have a shower pump.

Worth having one but there has to be a way to make them quiet, so no plonking them under the bath, the noise though the floor is too much.

[AliG]

Been to see the flats again.

 

What I thought was a big hot water tank was actually two tanks. Hot water below and cold water above.

 

The pump kicks in when you use a hot tap and gives good hot water pressure. I assume that the electric shower if necessary due to the small size of the hot tank.

 

There was good cold water pressure in the kitchen which presumably is connected to the mains and poor cold water pressure in the bathroom which is presumably connected to the cold tank.

 

Should I be able to replace both tanks with a UVC connected direct to the mains and do away with the pump and electric shower?

 

One flat had an e7 timer on the wall. The other just had a switch which said hot water and timers on the electric radiators which makes me think they have done away with e7.

 

 

[sharpener]

20 minutes ago, AliG said:

What I thought was a big hot water tank was actually two tanks. Hot water below and cold water above.

 

Fortic tank, common in flats before UVCs. Hence poor head (1 m if you are lucky) and need for shower pump.

 

Replace with UVC, all sorted. Use E7 if you can get it back, otherwise you will need a smart meter and their ToU tariffs.

[JohnMo]

41 minutes ago, AliG said:

done away with e7

We are on E7 it's all done through the single smart meter, no second required, no dedicated circuits, so that could be what's happened also

[AliG]

I think it would be cheaper to be on a time of use tariff now anyway.

[SteamyTea]

1 hour ago, JohnMo said:

no dedicated circuits

Mine has dedicated circuits.

 

[JohnMo]

4 minutes ago, SteamyTea said:

Mine has dedicated circuits.

 

Don't you get E7 tariff on all circuits or just you DHW and storage heaters? My meter only has a single tail going to a single consumer unit. So all cheap rate, or all expensive rate depending on time of day 

[SteamyTea]

All circuits at night.

Just saves having a timer to lock out the space heating and DHW.

 

Wires in and out meter.

 

Edited Wednesday at 16:22 by SteamyTea

[AliG]

Made an offer so in wait and see mode.

 

Not being a landlord I didn't realise all the changes to second home council tax, LBTT etc.

 

The flat is being used as a holiday home. So I am guessing the 200% tax will really sting. They have also upped additional property LBTT in Scotland to 6% of the total price. This also applies for a corporate purchase. So the value of places up for rent, which would be the main value of this place must have fallen.

 

My guess is that values should have fallen around 5% because of these two changes and this is not reflected in the home report valuation which was done before this.

 

I guess the purpose of the changes is to make houses a lot more expensive for landlords than owner occupiers and I think that is fair. I'm not going to have to pay this and it does look as if it is reaching the limits of what is reasonable.

 

TBH I'm surprised prices haven't fallen between this and interest rate increases.

[JohnMo]

Thought you were were putting in your daughter's name? Anything else will cost lots, second homes are expensive in Scotland.