Condenser boiler or heat pump

Cork22 said:
Debating about the one stop shop upgrade for about €30k (excludes windows but includes a new front and back door)
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Can you spell out what you are getting for your €30k OSS spend.


Cork22 said:
Gas usage 10,500kwh/year.

Electricity 6,000kwh/year.

House is 160m2
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It looks like you have a high A/low B rated house based on those consumption figures and usage pattern. This isn't that bad assuming of course that your house is comfortable etc. Some comments;
All else being equal, moving to a hp could save you somewhere between €200 & €500 per year excluding any solar/battery influence. This opinion is based on a heap of assumptions so cannot be really relied upon.

Your electricity consumption seems quite high, any reason for this? There could be easy wins here!

Cork22 said:
wondering will I still save money
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Likely you will save some money ... but enough to justify the investment???
 
@Micks'r thanks again for the response.

The below is 26k and I added 4k for a battery, I am meet the PM of the OSS company tomorrow to go through the details. I want to maximise the PV system and include a battery. I'll get a quote for windows too.

Roof - Ceiling Insulation
Walls - Cavity Wall Insulation
Door - Low Energy 1.0W/m2K (2 Doors)
Daikin Air to Water Heat Pump & Radiators
Block Chimneys (1)
Post Works BER Certificate
2.46kW PV System, Inverter & WIFI Monitoring (7k PC SUM)

High elec may be due to hot water usage, hot water tank looks modern but seems to run out of hot water after 2 shower (power shower). I need to change some of the light bulbs to LED too. Cooker is gas.
 
Your solar PV array is far too small at 2.46kw- sounds like only 6 panels? You should put as many panels on your roof as you can fit. The most expensive part of getting solar installed is getting the scaffolding up, so the extra panels will actually significantly shorten the payback period despite the higher upfront cost.

Also, if you're paying €7k for a 2.46KW system, you're probably getting robbed. If that's €7k ex-grant, you're definitely getting robbed. I paid less than that for my 7KW system after the grant.

Including a battery with such a small system is also pointless. I including batteries is pointless in general but opinions differ.

Honestly 2.46kW is such a ridiculously small PV installation that a big part of me things either that's a typo or you're just mistaken as to the size of system you've been quoted for. At such a small system for that price I'd skip it completely (and I love solar so much I usually use every possible opportunity to convince people to get them installed).
 
jim said:
Parts of house are cold other parts are perfect temp.
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Hey Jim. This should be easy to diagnose. Check that the rads in the cold rooms are actually working. Best to use a IR temperature gun for this (Lidl sell them for ~20 euro) because Heat Pumps run at lower temps it means just because the rads feel lukewarm, doesn't mean that they are not working. They should be roughly the same temperature as the rads in the other rooms. If they are working but at significantly lower temps compared to the (hot room) rads, then likely that you need to balance your radiators (or bleed them). If they are not working, then that's obviously a problem.
If they are working (i.e. roughly the same temp as the other rads), then they are undersized. The fix here is easy, replace them with larger radiators. Radiators are relatively cheap, and if your handy with a spanner, you can replace them yourself. (just get one the same width, but taller, or replace single panel, with double panel, double convector K22 type rads).

Correctly sizing your radiators will allow you to turn down the heat curve on the heat pump, which will increase efficiency and save you money on the electricity. This is the first thing you should do, before you do anything else.

Check out HeatGeek vids on YoutUbe.
 
BIG-notorious said:
Including a battery with such a small system is also pointless. I including batteries is pointless in general but opinions differ.
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My opinion would differ - if your battery is of sufficient size and/or you have other significant overnight electrical loads (e.g. EV charging) then a battery can totally make sense given the difference in EV/night rate versus daytime rates.

BIG-notorious said:
Honestly 2.46kW is such a ridiculously small PV installation
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Don't really agree with this either - a south-facing 2.46kWp installation should generate around 2,500 kWh per year, that's in and around 50% of the average household usage IIRC.

BIG-notorious said:
You should put as many panels on your roof as you can fit.
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Agreed!
 
conor_mc said:
Don't really agree with this either - a south-facing 2.46kWp installation should generate around 2,500 kWh per year, that's in and around 50% of the average household usage IIRC.
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Not at a cost of 7k it isn’t!
 
I don't have a size or price for the battery yet, I had the guy out from the OSS today to take measurements but he said he needs the PV, Windows and HP reps to visit before he can give me an accurately sized and priced quote.

The 7k does not include a battery or the 2.1k grant. I did ask if we could maximise the amount of panels but I'm limited as I have a semi d with 2 velux windows on the south facing slope. I have an extension with east and west facing slopes too. I'll wait to see what PV panel rep says once he has called around.

The house isn't zoned so gas heat rads and water together so I assume heating the water alone is cheaper with the electric heater. Night rate to charge the battery is part of the plan. I've no EV yet but I wouldn't rule it out in the future.

Once I have the full detailed quote I'll get it priced by another 2 contractors for comparison.

Do you think the HP will work efficiently with 20+ year old double glazed PVC windows, they seem OK.

Thanks for the feedback.
 
Cork22 said:
Do you think the HP will work efficiently with 20+ year old double glazed PVC windows, they seem OK.
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Heat Pumps don't actually care about your insulation and U values. It's only the SEAI HP grant that cares about that.
A correctly sized Heat Pump with correctly sized radiators will heat any space more efficiently than gas or oil.

However, there have been substantial improvements in Windows in the last 20 years. 20+ year old double glazed PVC windows (if they are working correctly) will have a U value of about 3.1
Modern double glazed uPVC windows have a U value of about 1.2, significantly better.
 
@AJAM that's technically correct. The best boiler will get 90% efficiency, while the best heat pump in ideal conditions will get 400% efficiency.

The SEAI has a list of cost per kilowatt heat output which they update monthly. The last time I checked the average cost prr kilowatt was 9c for a heat pump and 11c for oil which was the next cheapest.

But heat pumps are (for the time being) hugely more expensive than oil burners. And changing radiators could cost thousands more. For my home (fairly well insulated) I'd save €200 a year, so even assuming zero opportunity/finance costs it'd take decades to break even on the heat pumps. I'll look again when my oil burner eventually dies, but not before.

Given a choice I'd use HVO plus an oil burner for the best price-environment balance.
 
AJAM said:
Heat Pumps don't actually care about your insulation and U values. It's only the SEAI HP grant that cares about that.
A correctly sized Heat Pump with correctly sized radiators will heat any space more efficiently than gas or oil.
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I think they are probably asking about economic efficiency, which is unfortunately different to technical efficiency because a kWh of gas is so much cheaper than a kWh of electricity at the moment.
 
AJAM said:
20+ year old double glazed PVC windows (if they are working correctly) will have a U value of about 3.1
Modern double glazed uPVC windows have a U value of about 1.2, significantly better
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Is it worth the investment to upgrade i.e cost v benefit?

Thought our windows were triple glaze but theyre actually double glaze and about 20 yrs old!
 
I would say Jim, that no you should not upgrade windows, unless you are trying to achieve something specific e.g. you're trying to hit a specific target for heat loss to qualify for the HP grant, or you have a specific room, with massive windows that is cold.

If you just want to overall improve house comfort and running costs I would recommend going in order of payback
The info below is from the website https://www.greenmatch.co.uk/insulation
The pricing numbers might be a little out, as are the payback periods, but the order is pretty much correct.
Insulation typeCostsEnergy bill savings (£/year)CO2 savings (kgCO2/year)Payback (years)
Pipes & Water Tank£38£226
715​
0.2​
Loft£930£270
620​
3.4​
Cavity wall (270mm)£2,700£280
650​
9.6​
Solid wall (internal)£7,500£380
880​
19.7​
Solid wall (external)£12,000£380
880​
31.6​
Doors£840 – £4,325£45-
44.4​
Floor (suspended timber)£4,700£80
185​
58.8​
Windows< £15,000£165
375​
84.8​
 
Reactions: jim
I had the windows guy over to the house yesterday and it seems like replacing the glass might be a good compromise on investment vs return, plus they will service the windows while there to make sure they are sitting tight in the frames. Waiting on a price but I think it will be about 50-60% cheaper.
 
Are the windows well installed in the first place @Cork22 ? As in, a good airtight seal between frames and opes? There's that to consider. Also, the overall performance of a window is a combination of frames and glass. Newer frames may be more performant (more, better) insulation/materials than 20 year old window frames.
 
@David_Dublin to be honest I'm not sure but the window rep said the frames are decent and changing the glass will be a good benefit. He could have said no and pushed the new windows. New frames will definitely give you a lower overall U Value but is it worth the money, I'll wait until I have the quote with different options to decide. I may even do the other upgrades first, see how the heat pump is performing and decide on the windows a year later.
 
Make sure you get some type of documentation from the window supplier (after install). Ideally certs with the U Value. But if this is not possible, at least get on company headed paper the type of glass the U value and the date.
 
AJAM said:
Make sure you get some type of documentation from the window supplier (after install). Ideally certs with the U Value. But if this is not possible, at least get on company headed paper the type of glass the U value and the date.
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Agreed - super important for BER certification in the future
 
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