PIV is a flat advice please

agylk

I want to get PIV but I have learned that it only tempers the temperature by a couple of degrees meaning that in the winter there will be cold air blowing out of it. How awful with this being a small one bedroom flat? 

princeofpounds

Why not MVHR instead?

tacpot12

Just consider that if you didn't have a PIV, air that had had zero heating would be leaking into your flat to ventilate it. At least with a PIV, the air has had some warming. When the outside air is the coldest, at night, you will be tucked up in bed, and the cold air will likely be being introduced into the flat in the hallway, so you are not going to feel a cold draught. 

rob7475

When I bought our PIV unit, I got one with a heating element. It made very little difference to the incoming air temperature so I leave the heater part turned off now.

If the outlet is in your hallway, you'll not notice any noticeable drop in temperature in most of your flat. It's a very gentle flow of air and the design of the outlet means you don't feel a draught from it.

agylk

The flat is quite small and the hall is smack bang in the middle of all the rooms so it would be good for ventilation, not so good for the cold air. I have heard from people who said the cold air introduced meant that you have to pay so much more in the heating bills which is quite worrying especially right now. 
I know in a house the cold air is not so noticeable but it’s really worrying how it will be in a small flat. Especially that I’ve learnt you can’t turn it off once it’s installed. So if it gets unbearable, there is nothing I can do other than pay more for heating. 

I can’t afford a heat recovery system.

BUFF

why wouldn't you be able to switch off a PIV system once installed?
you can get single room heat recovery units for a couple of hundred £ if your flat is that  small.

rob7475

A piv unit can be turned off. The power will probably be taken from the loft space so you could either fit a smart plug to allow you remote control of it or wire it to a switched fused spur on the wall in the hall. 

You should find that it helps reduce humidity in your flat. Drier air heats quicker so you shouldn't end up spending more on heating.

Also, is there any particular reason for you wanting a piv unit? Are you having condensation issues? If so, do you have good extraction in your kitchen and bathroom?

agylk

Thank you. I wrote previously a long post about it but no one noticed it. In any event, after many years doing everything in my power to reduce humidity problems and smells in this flat, I am at a complete loss. No one has ever found any mould and I’ve had six specialist here including a surveyor. I’m at a loss so the only thing remaining is to install PIV. I also live very close to the sea. 
Nuaire told me it cannot be turned off and if I was to turn it off, it would be bad for the unit. I don’t know why. 

I think heat recovery units are expensive to run as well… 

BUFF

agylk said:

 

I think heat recovery units are expensive to run as well… 

if they used more energy than they saved that would be self-defeating ...

agylk

Doesn’t it cost like five grand to install?

BUFF

It depends what it is. If you were going for a full house MHVR system with properly sized unit for that & multiple ducting then ideally those are planned into the initial build (or a major renovation) & yes, the whole job in a house could easily run £7k. But you aren't planning that.