As part of our quest to make our house more efficient, we've installed solar panels, a battery, insulation, and all the other stuff you're supposed to do. The next step is working out if we can reduce our dependency on gas.
Octopus Energy (join and we both get £50!) offered to send an engineer around for free to assess our property for suitability for an Air Source Heat Pump (ASHP).
The engineer was friendly, knowledgeable, professional, thorough, and just full of bad news!
Here's a short summary of the issues they found:
- Siting of the ASHP. It can't be in view of the road, so it needed to be in our back garden.
Space for the ASHP. We had just about enough space on our back wall - given the existing pipe-work, doors, etc.
Surface for the ASHP. Needs to be on concrete or similar. We have decking (which, to be fair, could be removed).
Distance from neighbours. The ASHP makes a bit of noise - about as much as a washing machine. Regulations say that it has to be at least 8m away from a neighbour's window. Not possible in a narrow terrace.
The ASHP runs on electricity. Quite a lot of electricity. We'd need our main fuse upgraded and new tails. Both are possible - but the space we have in our utility cupboard is already cramped. Fitting in another distribution box would be disruptive. As would laying new cables from the front of the house to the rear.
ASHP requires a hot water tank. At least 100 litres - but probably closer to 200l. That's at least 200Kg of weight. While I think our loft could take it, their structural engineering calculations differ - and who am I to argue?
So where would the tank go? We'd either have to lose a bunch of space in a room or remove a cupboard.
Because ASHP run at a lower temperature than a conventional gas boiler, it was likely that our radiators would need to be upgraded to larger sizes.
On the plus side, the ASHP would work flawlessly with our Tado smart thermostat. Which is nice.
So, there we have it. For our tall and narrow terraced house, an ASHP just isn't possible without a lot of disruption and a significant change to the installation regulations.
We've been experimenting with Far Infrared Heating. Solid panels which directly heat the room. They're less energy efficient than a ASHP - but they provide heating pretty much instantly. They can be individually controlled, which should lower their cost. They're also plug-and-play so don't require any domestic remodelling.
We might move our gas hob to induction. That'll be quite expensive - and we don't use a lot of gas when we cook.
Hot water is the next big thing to tackle. An electric shower would work well. Using solar power to feed into the shower would work. But boiling a huge bathtub's worth of water is another matter. We either need a water tank and something like an iBoost to divert solar into an immersion heater. Or a heated tap. Or a not-yet-invented microwave boiler.
A little bit of a setback to our dreams of a more efficient house - but not the end of the world.