Installing a PIV system, which unit and should we have a radiator in the landing?

Ben1989

I'm fairly certain they only heat the air up to 10°C. Not worth it, in my opinion, not to mention the added installation time of wiring the heater in

rob7475

Ben1989 said:

I'm fairly certain they only heat the air up to 10°C. Not worth it, in my opinion, not to mention the added installation time of wiring the heater in

It won't work the same way as a standard fan heater you'd use to heat a room as they are constantly recirculating the air so it gradually gets warmer. The heater in the PIV is only heating the air that passes over it which is a constant stream of fresh air. In the current temperatures, you'll barely see a difference - if the air passes over at 2c, it might come out at 3c if you're lucky.

rob7475

rob7475 said:

tacpot12 said:

The 500w heater shouldn't cost that much to run as it should have a thermostat so that it only operates when the incoming air is much lower than the indoor temperature. If it is adjustable, I would have it set to 7C. 

You won't feel a lot of benefit from the heater if you put your hand into the airflow; it will still feel 'cold', but the heating system will notice the additional 0.5kW of heat being put into the house and it will stop the heating system from struggling. If it is struggling now, pumping cold air from outside (even at the relatively modest volumes that a PIV moves when not on boost) will make it worse. If you make sure the heater can be turned off, or adjusted, you will be always be able to manage the extra energy it draws. 

Most loft spaces stay cold though if they are well insulated so throughout winter, the heater would be running nearly constantly. I have a smart meter now so I might put the heater back on again so I can see how much it uses. I reckon it will be significantly more than the extra cost of running the boiler for a bit longer though.

I had a tinker with turning the heater back on on my PIV system. As expected, in the current conditions, it runs constantly and I feel no noticeable improvement in temperature on the landing.

My energy app shows that the heater must be running constantly as during the night my usage was 0.5kw an hour extra compared to my average overnight usage. At current prices, that would be about £4 per day to run the heater if it's on 24/7.

ashe

rob7475 said:

rob7475 said:

tacpot12 said:

The 500w heater shouldn't cost that much to run as it should have a thermostat so that it only operates when the incoming air is much lower than the indoor temperature. If it is adjustable, I would have it set to 7C. 

You won't feel a lot of benefit from the heater if you put your hand into the airflow; it will still feel 'cold', but the heating system will notice the additional 0.5kW of heat being put into the house and it will stop the heating system from struggling. If it is struggling now, pumping cold air from outside (even at the relatively modest volumes that a PIV moves when not on boost) will make it worse. If you make sure the heater can be turned off, or adjusted, you will be always be able to manage the extra energy it draws. 

Most loft spaces stay cold though if they are well insulated so throughout winter, the heater would be running nearly constantly. I have a smart meter now so I might put the heater back on again so I can see how much it uses. I reckon it will be significantly more than the extra cost of running the boiler for a bit longer though.

I had a tinker with turning the heater back on on my PIV system. As expected, in the current conditions, it runs constantly and I feel no noticeable improvement in temperature on the landing.

My energy app shows that the heater must be running constantly as during the night my usage was 0.5kw an hour extra compared to my average overnight usage. At current prices, that would be about £4 per day to run the heater if it's on 24/7.

Thanks for running the test - definitely not worth it then! Do you find it makes the house ant noticeably colder? That's my only concern as seen a few warnings about it but most say not a problem