What about the ventilation?

[T i m]

Hi All,

I got a cold call from one of the Solar Co's yesterday, "not selling anything Sir but just checking if you qualify for the grant" (or incentive, I wasn't really listening) ... and according to the guy who called back later I was. ;-)

However, after his spiel I explained I'd been there before and obviously had a rough idea of the numbers ... then we accidentally got cut-off?

That got me reading the recent 'FIT Slashed' thread, that covered insulation amongst other things and got me thinking about what I could do here (1897, solid 9" brick EOT 3 bed).

And that got me thinking about ventilation. If we are supposed to exchange the air every so often, I'm not sure at what point 'good insulation' is counteracted by all the cold air coming in from the outside?

So, how do we deal with that? Is it an issue? Why isn't there more talk of heat exchangers (I believe there has been some talk but not loads)?

Will that be the next top seller or scam, picked up by the Solar Co's?

Cheers, T i m

[Scott M]

Modern builds (esp in the eco & part funded sectors) are fitting air source heat pumps, heat exchangers for ventilation (IIRC Part L decrees it now anyway) and all sorts of gubbins. I was on site at Kevin McClouds development in Swindon the other month and they'd gone for the ASHP in a big way to the extent of not laying on gas.

[Dave Liquorice]

ASHP isn't the same as a heat exchnaging ventilator. The first actively pumps heat from a source into the building. The second uses something similar to a balanced flue where air is drawn in from outside and is heated by the warm air being expelled. They generally run at a low level all the time to provide background ventilation but if the humidity rises go into a "boost" mode.

[Dave Liquorice]

Air doesn't take that much energy to heat it compared to what you will have leaking out through the walls. 9" solid brick loses about

2W/m^2/K or about 20W/m^2 the room at 20C and 0C outside.

Being end of terrace you'll have acres of external wall. Bunging some internal insulation on, even just 25mm foam bonded to 12.5mm plasterboard will make a very noticeable difference to comfort and energy bill. Trouble is doing it is very disruptive unless you make it part of the decoration schedule.

[T i m]

Yup, and a road wide gap to the next terrace so normally a nice cooling breeze over the wall. It also gets the sun on it for the best part of half a day so can also be quite a nice storage rad. ;-)

Well, we haven't really finished decorating the hall yet so that wouldn't be a real big issue, however when the wall was re-plastered it was done with some plaster (or bonding possibly?) that was supposed to be better thermally? I'm guessing it wouldn't be anywhere near 25mm of foam though?

If fitting an inner lining we would have to incorporate the stairs and maybe flare it off near the front door but I can't see it being a real issue.

However, we don't have central heating either so when it gets real cold we just shut the lounge door and have the gas fire on a trickle and that seems to do the job (for us).

Another job I ought to tackle is some sort of insulation / sealing on the loft hatch as that is just a hinged sheet of 1/2" ply. With the loft ladders above I'm not sure how you would provide insulation without it getting in the way. Is there a nice ready-made (but customable size) solution out there ... like a sealed DG window unit?

And if I do seal everything up ... would I then need air heat exchangers to deal with the condensation? ;-(

When I bought this place over 30 years ago we never suffered with condensation but then it had the rattly sash windows as well. It was handy in a way as you already had your coat on if you decided to go out. ;-)

Cheers, T i m

p.s. The Mrs is *still* going through 'the change' and so is in no real rush to have this place any warmer.

[Martin Brown]

The foam rubber strip sold for windows should do as a seal unless it is a rattling good fit all round, and the foil backed polystyrene foam sold for putting behind radiators (the flat thicker stuff not the thin rolls) is about the most effective insulator in a small space. The aluminised bubble wrap might be better for the loft door though.

There was room on mine for a 2" slab of insulator which whilst nothing like as good as the full 12" is a lot better than nothing!

[T i m]

It's just a 1/2" ply 'panel' that is a reasonable fit (1-2mm gap all round) but straight into the 500W x 800L box I made within the joists when I opened up the hatch originally (as in 30+ years ago). It uses one of those push open - push closed type catches so there is nothing behind the flap as such (as I didn't want to make the aperture any smaller for getting stuff in and out). That said there is a small (15x15) bead round the inside at the bottom (that 'frames' the closed flap) that could come out if a re-design made getting it sealed / insulated easier (I think I put that in to give any architrave something more substantial to attach to).

I can see a block of that stuck to the back of the flap / door could be easy / good but was probably more concerned re draughts and the gap compared with the insulation of the wood / flap?

That's why I was wondering if there was some sort of ready-made door that you could fit 'over' the whole aperture (so on the landing ceiling if you like) that wouldn't require any reduction to the aperture whilst providing some reasonable insulation. The ceilings are reasonably high so even if it stuck down a few inches it wouldn't be an issue (and no one here would care less what it looked like). ;-)

At 6'2" and with gibbon arms I can stand and reach the door to open / close it and a little spring jump lets me grab the ladders. ;-)

Yup, that could work (certainly be better than the plain wood). I'm thinking if there was to be a seal then some of that brush type stuff fixed to the back of the flap might be better than nothing and not restrict the aperture at all?

I could get a couple of large plugs of polystyrene in there (overlapping or summat) that are just a good fit so stay there on their own (so over the flap but under the ladders) but it wouldn't be very convenient to use (and daughter 'hates' the noise and dealing with polystyrene). ;-)

Isn't there something in kit form with all the required seals and insulation out there? Like the roof light kits?

Ideally it might be a rectangular angle frame (8mm thick plastic?) that would sit in the hole and on the ceiling (al la architrave) but also allow for a good insulated door with proper rubber airtight seals (al la double glazed door / windows)? Such things must exist?

Cheers, T i m

[Martin Bonner]

Right. So decent ventilation for a Victorian terrace is not a significant cause of heat loss.

... having said that, for a house built to the Passivhaus standard (MASSIVE amounts of insulation, and airtight when ventilation is switched off) ordinary ventilation would be a huge heat loss, and they need heat exchanging ventilators. (They are sufficiently insulated that they don't need a heating system - they just use the heat from people/cooking/computers.)

[T i m]

.... so there would be no real / tangible advantage using (passive) heat exchangers in any ventilation?

We have even noticed that is this place when there are 4 people and 4 computers on, plus a TV etc.

So, given only the downstairs bathroom (Nth facing extention to the rear addition) is 'modern' construction (breeze blocks, insulated cavity, old stocks) and there isn't much in the way of other external wall facing North that isn't broken up with double glazed uPVC windows or doors, how much advantage would we gain from internally insulating the unheated flank wall or sorting the loft hatch do you think please?

Our bedroom (Sth facing) is heated by one 'intelligent storage rad, as is the bathroom. Daughters exposed_on_3_sides, Nth facing box room has a balanced flue, convection gas fire (that can get too hot on setting

1 of 3). The lounge has a 3 burner wall mounted gas fire that is rarely on full on 1 (normally thermostatically turned down once warm). I don't bother heating the kitchen since I bought her a nice winter coat. ;-)

We also have an electric shower and a Mulit-point gas water heater for the bath, basin and sink (we mainly shower and try to do so during the E7 time). The dishwasher and washing machine are cold-fill and along with the tumble dryer are mainly used on E7.

It can get a bit nippy between the warm zones but we are used to it and mankind has survived for millions of years with less. ;-)

Cheers, T i m

[jgharston]

I wouldn't like to live there, I like cooking on gas.

JGH

[fred]

Likewise, but it's not about what's right for the buyer, it's about hype, developer's margins and money in the endorser's pocket. Celeb chef gets a few bob for their name on pans and knives but can you imagine what you could make off the back of a housing development?

[Scott M]

Note the comma. I didn't say it was!