Property is a detached 5 bedroom 1960's build on the seafront in South Wales

Current spec. appears to be:
- 24mm DGU's, ~20-25 years old, numerous failed units
- Cavity wall - unsure if insulated
- Loft insulation ~250mm mineral wool
- Heating is a gas system boiler, gravity fed tank system with single radiators in every room
- Ground floor uninsulated

We would like to upgrade a lot of things and add a rear single storey extension but just wondering the best order to plan this project as we are also living in it?

On our list in a rough (what I think) order;
- Cavity insulation if not done so (EPS beads) any grants available?
- Insulate heating cylinder and lag pipework
- Installation of ASHP and cylinder - keep gas for now also?
- Take up ground floor, insulate and install wet UFH
- Remove all upstairs rads?
- Open up existing window openings for new designs/layout (assume EPS beads will stay in place being the newer glued type?)
- Install double/triple windows faced on outside skin
- EWI to front elevation
- Rear extension (block on flat with EWI) and knockthrough
- Double/triple glazing to rear and side elevations
- EWI to rear and side elevations
- Replacement roof with solar panels (South facing)

We need to do it in phases as we're going to be living here and we are also in no rush financially or stress wise to jump all in

What experiences do people have they can share? Or would you do the above in a different order perhaps? Maybe jump straight into the roof work to take advantage of solar power etc?

Thoughts appreciated

House link:
https://drive.google.com/file/d/1B-VpHGUqUlascnhMbsdKpxQxifg7WSUV/view?usp=drivesdk

Posted By: WillInAberdeenThe new mantra is "Fabric Fifth".

I think that's a little simplistic. For example, retrofitting a heat pump in a house without improving the fabric first will result in a larger (more expensive) heat pump being needed with consequent worse performance and greater running costs. As the abstract itself says "The suitability of a heat-pump-only approach to building decarbonisation should therefore be decided building by building."

Given the greater running costs resulting from a failure to carry out fabric upgrades, I don't think they're simply a matter of comfort or luxury.

I do think having an outline timetable for all the work is a good idea, to make sure it's compatible with climate necessities. In Gareth's case, I would probably delay installing a heat pump until the fabric improvements are done so changes to the heating system can be made once, and so the latest generation of heat pumps can be bought. But a lot depends on the overall timetable.

Posted By: VictorianecoAnd best website for heat pump sizing?

I really rate Heat Punk (https://heatpunk.co.uk/home) as a simple resource for drawing your building out and determining the heat demand etc.

Caveat: I don't have a heat pump myself, but I have played around with the interface and it is very user friendly.

We have decided to start with the bedrooms first (alongside the garden and driveway). We have ripped off all the skirtings, architraves and doors. Hoping to get the bedrooms finished first basically so the children's rooms are sorted.

This has meant raising the existing sockets so w are essentially going to rewire upstairs at the same time.

While the flooring will be up in going to put new pipework in ready for the ASHP (quote of £4k for Samsung unit and pre plumbed cylinder supplied and fitted) Will get a few extra quotes as this does seem high given that residue aren't included or electric supply or removal of the old system...

Would you run the main circuit in 22mm and rads at 15mm? We have this sad the existing arrangement but I can see going from a gravity fed system to pressurised will end in leaks somewhere.

Would you even use rads?? Maybe go for air to air heat pump on the landing area and just rads downstairs? Or how about plinth heaters coming out of the floor?

How would A2A work in a multi room property and hot water? I really don't think A2A is good for anything other than a small flat or 1 down/1 up type property

Thoughts?

Huge hotels are heated with A/A heat pumps (we think of them as the air-con system but they are A/A heating systems when 'run the other way') so they are not for small houses and flats only. And you can get HWCs with an integral exhaust-air HP.

Indeed, which is why I generally don't like EAHPs, unless it really is using 'exhaust air', such as in industrial processes. But if the alternative is an immersion heater then EAHP may be better (typical CoPs unknown), unless you are using solar thermal, or PV with a diverter.

A2A with a DHW feed are available. Google it.