I’ve been through all the information I can find on the internet about Zero Emmissions Boliers (ZEBs) to date having looked at ASHPs and had a couple of proposals. I don’t actually think our house is too badly insulated however, the repsonses I’ve got back including radiator replacements and hot water tanks have been in the £15000+ range. That set me looking at alternatives as I want to stop burning things to keep warm.
I just wondered if anybody had a ZEB running and would share their experiences?
We do have PV and battery already and do export to grid (last year 1372kWh) and currently have a combi boiler.
Hmmmm… Unlike an air source heat pump you don’t get any energy other than from the electricity consumed. There will inevitably be some energy loss from the stored heat but I guess as long as the boiler is within the house, and not, say, in the garage, then it’s still providing heating.
This is best used as an energy store during a solar glut (for those with PV) or to take off-peak power and store energy as hot water until needed during peak hours. It is indeed a zero emissions heat source locally but not fully zero emissions until the electric grid is itself zero emissions. The same is true, of course for heat pumps, except that they get more heat for a given amount of emissions.
I am working on the insulation and have MVHR installed, after experiencing additional condensation as I added insulation.
Biggest demonstration of effect of draughts is when I got rid of letter box and put on an external letter box. One of my cheapest changes for the benefit it gave.
BTW, did anybody see the 50% uplift on the BUS announced yesterday or am I imagining it? It will close the ASHP/ZEB gap a bit for me as I’ve been told I need several rads changed and a hot water cylinder added for ASHP.
You may not need to change radiators but I recommend making any singes into doubles or trebles and doubles to trebles. That way the existing plumbing will still fit. The higher the surface area the better. I actually recommend that even if you don’t have a heat pump as you can reduce boiler flow temperature and make it more efficient.
A high gain hot water cylinder is essential for a heat pump, unless you have a separate system for heating hot water. However unless you have a separate system already you have to include the DHW in the heat pump setup to qualify for BUS.
I’d agree with all the above however a couple of things to think about. Firstly how does the amount of power you export from the PV/battery compare with your heat demand. Also bear in mind that any additional electrical generation at present and for the foreseeable future will be met from gas so you will still be burning things.
One thing we have done is to adjust the temperature output of our existing boiler so that it is below 50 degrees until the outside temperature falls below zero. Even though many of our radiators are well over 30 years old only 1 room has been noticeably cold. Try that and you might get an idea as to whether or not new radiators are necessary.
I have used the abbreviations ZEB and nZEB several times in this forum.
To clarify, I have been using the abbreviation in the sense defined by the EU and in particular Ireland, where they stand for “Zero Emissions Building” and “nearly Zero Emissions Building”. I believe Northern Ireland has also accepted these standards into their building regulations. We have not, following Cameron’s “Cut the green crap”.
If there was a small enough system to fit into my kitchen I would take one to supply my downstairs hot water needs and isolate it from the rest of the house. I have unfortunately long pipe runs from my cylinder to the cluster of downstairs plumbing.
I realised yesterday that by the time I had adequate insulation to keep the system hot there wouldn’t be room for a meaningful amount of thermal storage.