Steamy Tea, you are spot on. As long as any significant part of our elec is generated by coal, then a heat pump needs a fabulous COP to make carbon sense. If we could cut elec consumption by 28% (the share of elec from coal), then CO2 from elec would fall by 56% since coal is twice the average carbon intensity.A 28% cut in elec use is dead easy technically, we just need to pesuade ppl to act on energy efficiency.

"Not until a brave government taxes the hell out of domestic fuel". OR a smart one: I am very taken by james hansen's proposal to give the carbon tax (charged upstream so equally on all sectors) back to ppl as a "dividend". Actually I would return to ppl 110% of the proportion of the tax which effectively relates to domestic energy, and use the rest to subsidise R&D on, and perhaps implementation of, energy efficiency and sensible renewables and CCS and nuclear. The carbon tax would dramatically raise the marginal cost of elec, so should be less difficult to persuade ppl to insulate etc.

'Sonoslot slotvents' are made with an wind operated damper. It closes off the vent automatically when it gets windy -simple but effective. They could be used to replace the existing outer part of the trickle vent in and existing house.

me too please

I just replaced the trickle vents on some 1990s double glazed windows. The old fittings had warped a little so they didnt quite seal -> cold draughts. The old ones had an internal shutter that flipped with a lever and a spring to shut it. The new ones are a better design where the moveable top flap pushes down onto the vent to seal it.

Very cheap and easy DIY job, draught fixed

Would be even easier to block the vents off but we do use them, the lock-open setting is a bit too far open for background ventilation on these windows.

Have got a window high up in the bathroom, where the trickle vent cannot be reached, except by standing on the sink... have blocked this one, as not used very often!

Agree with the OP that trickle vents are bad idea for airtight MHRV houses. (not like mine )

http://aereco.com/int/uk/thermics.php seems to work for me.

Having trouble with some of the other links.

Just tried again and the links are now working fine.