Maisonette in late-Victorian house, and aspirations for decarbonising it

[azps]

So here's the premise of the premises: I'm about to move into a maisonette in late-Victorian house, North London. Conservation area. Rear garden 110m² with no road access; 80m² internal floor space; 2 storey; single-glazed; old combi gas boiler; roof belongs to other flats in the house, and is 2 stories above, so very unlikely to be an option of solar thermal.

Proposition at this stage: secondary glazing (selectaglaze or similar); testing for air leaks and sealing up; considering MVHR; not looking to do this as a charity-job, so stuff has to pay for itself (call it a 4% discount rate)

And other complicating factors: there's a danger of a need for some kind of cat-flap. There will be discussions about the presence or otherwise of a smokeless fire of some description.

Thoughts? Elephant traps I should beware of? Recommendations for tech, installers and suppliers?

[stannn]

Magnetic cat flaps actually have very low air leakage.
Stan

[brackwell]

I am presuming you have a basement 2 storey maisonette in a terraced block of Victorian houses. 
Your biggest heat loss after window and door draughts will be through your ceiling into the upper maisonette. This is relatively cheaply rectified by using a suspended ceilng arrangement. These are made to allow maisonettes in particular to satisfy the latest noise regulations and are a off the shelf kind of product.  If at the same time you insulate with well fitting insulation you will get a two birds with one stone.

I presume you have a suspended wooden floor and this can be cheaply insulated if you are a DIYer

Check you have not got heat going up the chimney -if you have block it off.

I suggest you attend to these points before thinking about heat inputs as you will find they give a large reduction in heating requirement and you then may decide to leave the status quo.

Ken

[solar_cambridge]

for the catflap, an airlock type arrangement with an external and internal door. External door to be a 'Pet Porte' to only allow your cat in. Going through wall would be better than the door which could compromise security and be harder to draughtproof.

[azps]

Hi all, thanks for the feedback. It's an upper-ground / lower-ground floor maisonette - so upper-ground is at street level, lower-ground is at garden level. Yes, it's terraced block. Garden faces SW. Cat airlock sounds a great idea. I don't yet know what the floor construction is - I will do in a few weeks, when we move in. I'd quite like to get rid of the gas boiler altogether, if possible, and am looking at the alternatives. Suspended ceiling should be easily doable ... apart from my better half looking forward to the cornices & ceiling rose. I think they've previously been taken off and reattached, so there may be an option to reattach them to a suspended ceiling.

Any recommendations on particular suspended ceilings, combining decent sound insulation and thermal insulation?

[JohnH]

Hi AZPS
If you have a Victorian terrace then presume you will have solid exterior walls front and rear? As suggested on an earlier thread, dry-liner insulation such as Gyroc Thermaline Plus dot and dabbed to the inside of exterior walls would be a good investment.
JohnH

[azps]

I'm pretty sure that they are indeed solid exterior walls front and rear. How does the Gyproc Thermaline Plus compare to the Kingspan K-17? (of which I've heard good things, but have no direct experience) Are they pretty much the same thing (cost, thermal performance, vapour control, ease of working with)?

Regards,
Andrew