Condenser boiler or heat pump

H

Haille

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I got 16 panels plus two 5kw batteries installed a year ago in a 1989 dormer bungalow.

Recently I got the walls pumped with bead insulation and attic insulation.

I have a 35 year old oil burner that is still going well. The plumber that put it in told me the lifespan of condenser boiler could possibly be 15 years. I paid 280 for a BER cert for panels last August. If I wish to claim the insulation grant I have to get another BER cert. I thought if I upgraded my boiler to a condenser boiler and installed a few thermostats for rads I would qualify for 700 euros heating upgrade grant and get the one BER cert to cover insulation and heating upgrade.

My question is would it be better to go for a heat pump? Though it is a 1989 house with no underfloor insulation so not sure if a heat pump would work as I assumed it requires max. insulation to make it viable? any thoughts?
 
To get the SEAI grant for a heatpump you’ll need to have a heatpump technical assessment done, which will give you a good sense of whether the levels of insulation, windows etc are sufficient for a heatpump to make sense. The only thing to watch out for is they pay zero attention to air tightness, so if you find the house drafty (very common in Irish dormers because of how they tend to be built!) you need to factor that into the results you get back from the assessment.

Regarding the solar PV, bear in mind your heatpump will mostly be running in the winter and during the night in the summer (to make use of the night rate), the two times when your solar panels generate very little.
 
Haille said:
My question is would it be better to go for a heat pump?
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Haille said:
I have a 35 year old oil burner that is still going well
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If your oil burner is 35 years old, then I assume your radiators are equally as old?? If they are then they are more than likely not suitable for a Heat pump. You need to have low temperature radiators or underfloor heating that transfer the heat at much lower temperatures.

Haille said:
I assumed it requires max. insulation to make it viable? any thoughts?
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Not necessarily, good insulation is very helpful but probably more important is the air tightness of the house. If you have lots of draughts then it may not be airtight.

If your home has always cooled down very quickly as soon as the heating is turned off then you probably have a leaky house that is not airtight and not currently suitable for a HP.
 
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It really comes down to an assessment on whether the heat pump would be cheaper to run in the long term.

You'll need to factor in how much it will cost to switch and how much it will cost to run versus how much are you spending on oil now. Bear in mind heat pump systems are not as responsive as boilers, and so need to run longer to provide the same level of heating.
 
As alluded to by a couple of other posters, insulation and even air tightness are both significantly less important to heat pump efficiency than appropriate sizing of the overall heating system (i.e. pipe diameters, radiator sizes) so that the system can run at a low flow temperature (35-45 degrees) and still overcome the heat loss through the building fabric. As one heat pump engineer said, "they use heat pumps to heat marquees for goodness sake!" - it all comes down to heat energy in equaling heat energy lost, and doing that at as low a flow temperature as possible. In terms of running costs, you can assume an appropriately designed system will run at a coefficient of performance of at least 3.5, sometimes up to 4.5, so if your electricity price is less than 3.5 times the price per kwh of gas/oil it'll be cheaper.... generally electricity is around 3x the price of gas at the moment so not a huge saving, but generally results in a more comfortable home as heat is maintained rather than boiler off/temp drops followed by boiler on/temp rises. Strongly suggest checking out the Heat Geek consumer series on YouTube.
 
conor_mc said:
so if your electricity price is less than 3.5 times the price per kwh of gas/oil it'll be cheaper....
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Most heat pump systems here seem to be specified on the assumption that they will run for much longer periods to compensate for the lower running temps and slower response times. While high-temp heat pumps are available, I don't see them referenced too often.
 
I have solar panels and switched from a (new and relatively efficient) gas boiler to a Heat Pump.
My annual gas bill of 850 euro has disappeared.
My electricity bill has gone up by about 400 euro.
So I'm saving roughly 400 to 500 euro per year from switching to a Heat Pump.
 
I will eventually add a Home Battery, which should enable me to run the heat pump almost entirely on cheap rate electricity.
This would mean the annual cost to run the heat pump would be closer to 150 euro.
Making the saving somewhere around 700 euro. But whether you count that as heat pump savings or battery savings, I don't know.

My philosophy on it, is that Electrification is actually an Ecosystem. Solar Panels, EV's, Heat Pumps and Batteries - each of them magnify the savings of the others. E.g. Solar Panels and Heat Pumps, there are large portions of the year, where during the day, my panels cover all the electricity for the Heat Pump. But even in Dec/Jan when they do not, the heat pump uses all the solar generation, which means I get the full value (35c) of my solar generation vs the 22c when you export it.
 
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That’s a great result. Mind if I ask about the building structure/fabric?
 
conor_mc said:
That’s a great result. Mind if I ask about the building structure/fabric?
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New Double glazed windows (U Value 1.4)
Walls insulated with 50mm PIR insulation (U value 0.3)
Floor insulated with 75mm PIR
Roof insulated with 300mm or 400mm of earthwool

For the Heat Pump I had to upgrade 1 radiator as well as the hot water tank and the pipes.
 
Like the OP I am in a dormer and trying to figure out re potentially switching from a gas boiler (on its last legs) to a ASHP. My home is a bit of a mixture of a house built in the late 1930s, a 1990s dormer conversion with a modern 2020's extension at the back. Overall the insulation arising from work we have had done over the years, apart from the dormer ceiling, is reasonable with UFH in the modern piece.

From the bit of research I have done on-line, there seems to be examples in the UK where ASHPs were fitted to properties with poorer insulation etc than my own. However, it seems to be installed by guys who are at the very top of the game in terms of knowledge how to fit /commission these Heatgeek / Urban Plumber / Gwyn Hudson etc. Generally here there seems to be a lack of knowledge around these systems, particularly in more complex installation settings? Maybe it will change. Also I have a suspicion the grants system - while trying to nudge behavior and better installation standards has created a very expensive equipment and installation cost environment. Basically the industry has priced in the Government's wedge.
 
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Can I ask how 'up-to-spec' your property was in terms of insulation (i see you have details above) airtightness etc? Did you need to do much enabling work?

In terms of your gas heating system did you have to do much in terms of pipe upgrades etc ? You are currently saving €400 per annum, how much did the upgrade cost you (if you dont mind me asking)? For a lot of folks guys like you are very interesting case examples of those who have taken the plunge and have a good experience to share. Thks
 
Probably a stupid question, but if heating systems for heatpumps need to be designed to run at 35-45 degrees, how do you get decent hot water temps? Or is that provided by a different heating system, or heated as needed via a different hear setting in the heat pump?
 
The heat pump will generally stop sending water to your radiators for an hour or two during the night and just heat your domestic hot water tank, shooting for a higher temperature like 50 degrees or so.

Out of interest, ours used an average of 1.6kWh a night to heat domestic hot water in August, so €0.30 a night. That’s for two long adult soaker showers every day then a couple of big children’s baths a week.
 
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Thanks @Zenith63 - so HP would need a hot water tank, and potentially using an immersion or boost feature if more hot water needed for night time. I went with a gas combi boiler when I refurbed, I'm happy with the results butI definitely wasn't 100% certain about not going HP.
 
Reactions: jim
Yeah definitely needs a tank, it cannot heat water nearly fast enough to operate like your combi. Ours has a 300L factory-insulated tank in a cold garage, heats at 1am for an hour or two then we have hot water for showers and baths at 8pm the next day without issue. Modern tanks are fairly incredible.
 
Very interesting topic above, any further info on the subject?

I have 20 year old double glazed windows but the house has had the cavity walls pumped and attic insulated.

Debating about the one stop shop upgrade for about €30k (excludes windows but includes a new front and back door) and wondering will I still save money. Sounds like I will if system sized correctly. I am also going for Solar PV with a 5-10kw battery. Thanks.
 
One thing to bear in mind, as a lot of people found out recently, a Heat Pump won't work if you have no electricity.
 
And also worth noting, a boiler will also not work if you have no electricity. Though you do have more of a shot of getting a boiler working with an electric vehicle 230V output, solar battery or a generator than you do with a heatpump due to how much electricity a heatpump needs.
 
Cork22 said:
wondering will I still save money
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Who knows... there are many variables at play.

What type/age history of house (the more detail the better)?
What heating do you use now?
What amount of fuel do you currently use?
Does the house heat up quickly?
Does the house hold its heat... i.e. within an hour of heating going off do you notice that it has gone off or not?
What's your normal heating regime (how long is the heating on daily and / or what temperature do you keep the house etc)?
Do you have any condensation / damp / mould issues?

What you have to remember is in order to have a comfortable internal temperature / environment, heat input from your heat source needs to match your heat loss. In my experience of OSS / grant aided measures, too much emphasis is on the supply of heat rather than the reduction of actual heat loss. Most people think (because the media and industry want you to think) that the main issue with heat loss is insulation related (conductive heat transfer). Whereas, the actual main culprit for heat loss in the majority of houses is convection losses, i.e. draughts or air leakage.
So, whatever you do, make sure you have a proper handle on where your actual heat loss weaknesses are before deciding your plan of action.
 
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