Heat pumps

[first mate]

Is external rendering of old brick structures advisable? Don't bricks need to breathe? Genuine question as, from what you say, anyone with an old victorian or Edwardian house is probably going to need to render externally to get sufficient insulation?

[Cozza01]

Hi

Render is not my field of expertise! The thermal render we used is "breathable" so not an issue. You are best speaking to the people who install but to share

1. We used external thermal render where we had existing render (upstairs back of house and upstairs down the side return.)

2. All the other rooms we used internal insulation in the external walls of those rooms only.

Hope that makes sense.

[JamesRixon]

Good Afternoon,

My name is James Rixon and I am director of a local Architecture practice rixon architecture. We specialise in low carbon and sustainable design with a particular interest in retrofit.

Am really please to hear this being discussed as a topic, I have actually just responded to someone on a separate thread about internal wall insulation which I have copies below.

My current understanding is that yes you can heat your home with a heat pump, and there is a chance you may have to change your radiators due to output size. it will likely cost 10-16k to install and even though they are extremely efficient in terms of units of heat out compared to units of energy in you will end up paying more for your heating without additional measures due the cost difference between gas and electricity.

A few tips on internal wall insulation:

make sure all wall papers and substrates are removed before installation as these could encourage mould growth.

Consider ventilation improvements.

Think about junctions with wall, floor, ceilings and windows as there is a risk of creating an acute cold bridge.

Consider vapour permeable insulations to limit moisture getting trapped against the cold outer wall

and applying brick cream to the external wall which limits the adsorption externally

look at natural materials as carbon saving can be made not just in the operation of a building but also with that materials used.

We are currently developing tailored reports for clients for a reduced fee starting at ?200. This would include a site visit, and visual survey and then go on to outline an appropriate retrofit plan along with advice on how to approach this in stages. If this could be of use to you please get in touch.

All the best

James Rixon

[redpost]

cidolphus Wrote:

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> From a physics case this is correct but the drop

> off is marginal and does not impact the warmth of

> the house because air source heat pumps work best

> in insulated houses. (Heat pumps are used in the

> Nordic countries which are significantly colder

> than the UK.)

>

> My advice would be...until you have completed the

> following list of energy improvements....its not

> going to work that well in a victorian/edwardian

> house which just leaks heat. (No cavity wall

> insulation.)

>

> 1. Decent double glazed sash windows

> 2. Wall insulation - either inside or on the

> outside of the house...depending on if your house

> is brick or render. Insulation only needs to be on

> the external walls.

> 3. Under floor insulation plus and perhaps under

> floor heating - most houses are floorboards over

> dirt foundations not exactly robust from a heating

> perspective. (We have underfloor heating on the

> ground floor and radiators on the first and second

> floors.)

>

>

> The bit about heat pumps "working best" in well

> insulated houses is nonsense because ANY heat

> source "works best" in a well insulated building

> simply because there is less heat lost to the

> outside.

>

> The steps to minimising heating costs are:-

> (A) double glaze (or triple glaze all windows as

> they do in Scandinavia)

> (B) insulate every external wall and (

> © draft proof external doors. Do all that

> properly and you will save a massive amount.

>

> Heat pumps are over-hyped - similar to the hype

> that a "smart" will meter will save you money. A

> smart meter doesnt save you any money whatsoever.

I believe the problem is the classic UK problem, which is poor design and build standards in this country.

[Dogkennelhillbilly]

redpost Wrote:

------------------------------------------------------

> I believe the problem is the classic UK problem,

> which is poor design and build standards in this

> country.

The design and build standards in the UK a hundred years ago - which is when most of the houses around here were built - were pretty good.

[thursday]

Can I thank everyone for their comments and suggestions on this thread. My apologies for not replying earlier - work pressure.

My house is not even close to well insulated. As one thread poster suggested, the ground floor boards are just laid over joists with no insulation beneath. The loft has minimum insulation and the external walls are not insulated at all. It feels like this is the right place to start and a no regrets place to invest.

I am still very much interested in installing this tech and will be keeping an eye on both ground source and air source pumps become more energy efficient, while I work on the insulation. I think the new Government scheme may encourage more investment in this sector.

It really feels like moving from fossil fuel is the way to go, but maybe that's in incremental steps for me. I'd really like this thread to keep going as the science develops, so all new thoughts and views would be great to hear. Thanks

[DiD]

We insulated, and changed all of our windows, etc... And now have just installed a hot water tank, which we'll connect to solar power (Solar PV). So this means our gas consumption will just be for heat...total cost will be less than 2K (though my husband did some of the work himself), as we can use our existing combi boiler just for heat. Putting in a ground source pump wasn't feasible nor was an air source one as it would require lifting up all of the floors, and we have a small garden. But at least this plan will reduce our carbon footprint and our gas and electricity bills overall. You can also get solar thermal and not need solar PV.

[redpost]

Dogkennelhillbilly Wrote:

-------------------------------------------------------

> redpost Wrote:

> --------------------------------------------------

> ----

> > I believe the problem is the classic UK

> problem,

> > which is poor design and build standards in

> this

> > country.

>

> The design and build standards in the UK a hundred

> years ago - which is when most of the houses

> around here were built - were pretty good.

Sorry, I was referring to new builds: missing insulation, cheap insulation (using glass wool rather than PIR), insulation stuffed in openings only so looks like whole wall insulated, poor airtightness, cheapo UPVC window frames and general poor quality of build.

When refurbing my house, I did all the insulation myself simply because I couldn't trust any builder to do it properly.

[Nigello]

Thursday - you can save energy and at least some money by filling in the gaps of your floorboards with https://stopgaps.com/ , and also by lining curtains, blocking draughts around doors and windows with tape, etc.

[Sue]

Nigello Wrote:

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> Thursday - you can save energy and at least some

> money by filling in the gaps of your floorboards

> with https://stopgaps.com/ , and also by lining

> curtains, blocking draughts around doors and

> windows with tape, etc.

I use StopGap, but my living room floor is still very cold. I do have some rugs.

I can't insulate the floor from underneath because my cellar is mostly filled with rubble, so I can't get at it. I believe this is from when the house was first built (it's an Edwardian/Victorian terrace, and someone once told me the builders put all their rubble into every fifth house's cellar. No idea if that is true).

Has anybody insulated their floor from above, by taking up the floorboards, and if so how did you do it?

[redpost]

I screwed in underneath the joists some marine ply strips (18mm thick, 1.2mm long, about 200mm wide) perpendicular to the joists

... lucky had enough clearance underneath to get a right angle cordless driver in. These strips will support the solid foam insulation between the joists and still allow airflow.

If one was to just stuff the hole subfloor with rockwool/glasswool, there would be no ventilation to the joists and they'd get damp and rot.

The joists were 220mm deep, so put first layer of 100mm celotex insulation ... loose fit, expanding foam the edges ... then but a second layer in + foam and topped off with 20mm insulation + foam

Wood is a good insulator, so no real need to insulate on top, but another 20mm wouldn't hurt if you have the depth.

Don't try and cut insulation exactly, just undercut it and get a good foam gun ... most builders don't realise cold air will just bypass insulation through gaps.

While you've got the floor up: make sure no rot, check any mid joist supports are good (usually a few bricks) and make sure air bricks are clear ... if you block off the ventilation to the subfloor, then you'll get rot.

[mac4]

I've insulated under my ground floor by cutting a small square hatch in the floorboards and then sliding about on my back pushing insulation up between the joists and holding it in place with wire netting stapled to the underside of the joists. Be sure to electrically bond the wire netting to any adjacent metal pipes, earths etc. This was years ago and it's made a substantial difference.

[redpost]

PS. I don't know your exact situation, but clearing out the cellar is the option I would explore. You can then insulate from underneath and avoid ripping up and replacing the floor ... it's a pain to get old floorboards up without damaging them and you may have to remove skirting as well.

[Sue]

redpost Wrote:

-------------------------------------------------------

> PS. I don't know your exact situation, but

> clearing out the cellar is the option I would

> explore. You can then insulate from underneath and

> avoid ripping up and replacing the floor ... it's

> a pain to get old floorboards up without damaging

> them and you may have to remove skirting as well.

I agree that would be the ideal option, but I suspect clearing out the cellar would be massively expensive.

Who would do that kind of work? A general builder?

My floorboards are a bit of a mishmash, and are painted white, so I'm not too bothered about damage as they need repainting anyway.

[Sue]

mac4 Wrote:

-------------------------------------------------------

> I've insulated under my ground floor by cutting a

> small square hatch in the floorboards and then

> sliding about on my back pushing insulation up

> between the joists and holding it in place with

> wire netting stapled to the underside of the

> joists. Be sure to electrically bond the wire

> netting to any adjacent metal pipes, earths etc.

> This was years ago and it's made a substantial

> difference.

Is there any reason why the netting needs to be wire, rather than plastic?

I have no intention of sliding about on my back beneath the floor 😂

[mac4]

I don't think so but a metal mesh has more flexibility when installing (can be scrunched up, stretched and pulled about).

[redpost]

I did my upper floors with wire mesh and rockwool, this was necessary for fire resistance since it will stay in place during a fire.

On my ground floor I used ply strips as I found wire mesh more fiddly in this situation and couldn't get my power stapler into the space. I was also able to bed the celotex slabs down on the ply strips with foam for airtightness.

Insulation is a big disruptive job, but it makes your house extremely comfortable if done well ... need to pay attention to ventilation and air tightness. On a cold winters day, around 7pm before the heating kicks in, my upper floors still have retained heat from the morning when the heating turned off 12h earlier.

[Townleygreen]

With regard to Sue's comment about not wanting to slide about oin one's back under the floor, I have found a firm called Q-bot https://q-bot.co/

who use a robot device to spray foam under the floorboards. Not sure, but could be a help?

[Sue]

Townleygreen Wrote:

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> With regard to Sue's comment about not wanting to

> slide about oin one's back under the floor, I have

> found a firm called Q-bot https://q-bot.co/

>

> who use a robot device to spray foam under the

> floorboards. Not sure, but could be a help?

Thanks, I'll have a look!

ETA: Unfortunately the robot appears to work from the cellar floor, which would be impossible in my case because of the rubble.

[clive]

Hiya

I have a Daikin air source heat pump and need to have it serviced as a condition of receiving the Renewable Heat Initiative grant. I wouild welcome any details of reliable contractors and roughly what will they charge.

Clive