Transform warm air system from Gas to Electric.........possibly.

[merlyn]

The house is a late 70s detached in the South West, with good insulation and 20years old double glazing. It has a B EPC. Currently it has a Vaillant boiler and a Johnson and Starley warm air unit. The hot water causes the J&S unit to turn and blow the warm air it collects from the boiler's hot water. It then it heats the house. Or doesn't if you run the boiler cooler to save energy/money. Hardly any warm air reaches the upstairs. Not that that is a big problem with electric blankets. 

We have solar panels (3.9 kW) from 2014 so relatively unsophisticated and a Tesla battery. The house, in winter is heated by gas and the battery is charged up on cheap overnight electricity. The house runs on just the panels and battery for 9.5 months of the year and the rest is mainly gas and a bit of electricity thrown in. 1.5kWhs are generated in December and 2.5in January. Have 15kWh altogether per day. An Electric car is charged on cheap rate too and we have about 8.5Kwhs electric for heating before it goes up to 41p a kWh but can run the gas downstairs if needed. The hot water is gas. We will probably keep the gas but steadily replace it, then use it in an emergency. 

Initially I will test the water on here to work out the best way to adapt the warm air heating (WAH) to an Air-to-Air heat pump. (If you are not familiar with A2A they are Air conditioning units running in reverse.) 

The outside unit (3 connections minimum) will be mounted on the end wall with short run to the lounge unit (2.5Kw) and one other connection has a run of 7 metres to the "warm air distribution point" in the centre of the house. see photo Plenum. This will have to be modified to accept a "Ducted" unit, unless  anybody knows better.

The upstairs unit will only heat 1 room at a time (bathroom/study mainly) and therefore can be relatively low powered. 2.5kW again?

 

 

 

 

[RichardL]

A2A challenges so far

1. control out of the box
If you go whole house the default is a remote per inside unit and takes a little work, extortionate for what it is from manuf. to build a more useful system. I guess unless you go ducted and build on your existing system infrastructure - if you can - only one unit = control will be fine.

2. inside unit locations
Installers like to mount on outside walls - anything else needs a little planning

3. bathrooms challenge
Unless you have ducting - and even then getting A2A anywhere near wet environments needs some work or alternatives.

4. Need an alternative for DHW


Otherwise its great - feels much more suitable for a more leaky house than A2W - not as critical to get the sizing just right plays closer to the 'I need this room hot now' mindset. You can also try it out in one room first - provided a little planning on which outside unit to invest in for later expandability.

[JohnMo]

Have a search on here, someone did this or very similar not that long ago, thread contains lots of details