Decision Time!!!!

muinteoir

We are just about to make last decisions about our house. The house will be about 3200 sq ft doormer. It will have passive windows, well insulated, air tight membrane etc & solar panels. We have talked experts/ engineers/ plumbers/ architects but are still unsure. Should we go with-
Rads & Oil
UFH downstairs, rads upstairs, HRV, Oil condensed boiler
Or the above with geothermal instead of oil.

Would love to hear from experts/ someone who has built in the last few years. Were meeting builder in a week to decide!

Thanks.

BryanF

muinteoir wrote: »

We are just about to make last decisions about our house. The house will be about 3200 sq ft doormer. It will have passive windows, well insulated, air tight membrane etc & solar panels. We have talked experts/ engineers/ plumbers/ architects but are still unsure. Should we go with-
Rads & Oil
UFH downstairs, rads upstairs, HRV, Oil condensed boiler
Or the above with geothermal instead of oil.

Would love to hear from experts/ someone who has built in the last few years. Were meeting builder in a week to decide!

Thanks.

Whats your Provisional BER results, outlining renewable requirements to meet building regs?

fclauson

Also - have you done a PHPP

if you house is very well insulated then I would go for UFH and a heat pump either air-2-water or groundsouce - depending on price

Not sure about upstairs - we are a bungalow - but we have a HP - and NO THERMOSTATS - we leave the HP to control everything - working out at about €3 per day

REMEMBER all thinking about rads and thermostats assumes a up-down-up-donw-up-down temp fluctuation. In a thermally efficient house its same-same-same (our house sits at around 20 to 21 all day and all night)

Tommyboy08

fclauson wrote: »

Also - have you done a PHPP

if you house is very well insulated then I would go for UFH and a heat pump either air-2-water or groundsouce - depending on price

Not sure about upstairs - we are a bungalow - but we have a HP - and NO THERMOSTATS - we leave the HP to control everything - working out at about €3 per day

REMEMBER all thinking about rads and thermostats assumes a up-down-up-donw-up-down temp fluctuation. In a thermally efficient house its same-same-same (our house sits at around 20 to 21 all day and all night)

As its a new build exhaust all your other heat pump options(ground source or borehole) before you use air source, they really should be a last resort as their performance at anything below 2degrees is shocking, I fix heat pumps every day of the week and there really is a huge difference between ground and air as well as between different manufacturers, and unfortunately in this country the biggest difference is in the installers,
Also don't mix ufh and rads, fan assisted rads if you can't do underfloor upstairs

fclauson

Tommyboy08 wrote: »

.... last resort as their performance at anything below 2degrees is shocking..

When looking at this you have to do the maths - yes its true the air temp is below 6 or 7 degrees ground source pumps are better because the ground temp is typically that sort of temp but for all other times air source is better

now look at this http://www.ireland.climatemps.com/#metric

you will note that the average temps are only below 6 or 7 for a very short part of the year - so this type of decision is not as simple as it seems

also you will need to check you soil type is right for a ground source - it needs a regular flow through of rain to bring that surface warmth down

if using a bore hole make sure you get it installed properly and that does not mean hanging the pipe down the hole - it should be plugged & grouted

KCross

muinteoir wrote: »

We are just about to make last decisions about our house. The house will be about 3200 sq ft doormer. It will have passive windows, well insulated, air tight membrane etc & solar panels...

One point, if you do decide to go for GeoThermal you probably do not then need the solar panels as well.
I have a Geothermal HP(UFH downstairs and oversized alu rads upstairs) and the amount of electricity it uses to heat water is very small. The full cost(heat & water) to run the HP for the year inc vat is about €1000 (3700 sq ft) and I'd estimate the hot water portion of that is €100-€200 at most and thats for a busy house with 3 kids!

With those figures you couldnt justify spending €4k-€5k on solar panels as well. The payback is 20+ years which makes it not worthwhile.

So, when deciding on the finances for Geo, put the €5k you have put aside for solar and put that against the HP cost.

I would also disagree with fclauson on the thermostats. If you have rooms that you dont use, why heat them to 21C. Also, you would typically have your bedrooms a degree or two colder than living areas. Its just more comfortable that way. So, I'd be for having thermostats but it is probably a personal decision as opposed to being right or wrong.
I have digital stats in each room and it is good confirmation that the system is working as you get a digital read out of the current temp as well as the set temp.

fclauson

KCross wrote: »

..

I would also disagree with fclauson on the thermostats. If you have rooms that you dont use, why heat them to 21C. Also, you would typically have your bedrooms a degree or two colder than living areas. Its just more comfortable that way. So, I'd be for having thermostats but it is probably a personal decision as opposed to being right or wrong.
I have digital stats in each room and it is good confirmation that the system is working as you get a digital read out of the current temp as well as the set temp.

OK - but where with MHRV & super insulation the whole house levels at one temp over time

Tommyboy08

fclauson wrote: »

When looking at this you have to do the maths - yes its true the air temp is below 6 or 7 degrees ground source pumps are better because the ground temp is typically that sort of temp but for all other times air source is better

now look at this http://www.ireland.climatemps.com/#metric

you will note that the average temps are only below 6 or 7 for a very short part of the year - so this type of decision is not as simple as it seems

also you will need to check you soil type is right for a ground source - it needs a regular flow through of rain to bring that surface warmth down

if using a bore hole make sure you get it installed properly and that does not mean hanging the pipe down the hole - it should be plugged & grouted

The only time of the year that air source is better than a proper ground source system is when the outside temperature is such that there is little or no demand for heating,
Ground source units will work fine in drier ground particularly DX type as the ground temp will recover during the summer months, a well designed ground system coupled with well designed underfloor will achieve COP's of 7 and harsh winters will have little bearing on their performances,

Air source on the other hand have a lot going against them,
COP's of little more than 4 at 7degrees but as we have a very humid climate they spend a lot of time defrosting where they have to take some of the heat that they fought hard to create in the first place with their poor COP,s and use this to defrost their coils, which is very wasteful, along with the need for a buffer tank for defrosting, more expense
Add this to the fact that you will need a back up heat source for colder temps which is more waste and can you see any of these lasting anywhere near 20 years in someone's back garden before they fall to pieces, and that's if you didn't buy the absolutely rubbish Chinese ones that are flooding the market,
As for the boreholes, of course the only way it should be done is grouting the bores as it is done by proper geothermal companies not these idiots that seem to think 200 meters deep is acceptable and that pea gravel is a suitable material for backfilling the bores,
We really need some proper education about geothermal heating in this country and I don't just mean education for the people looking to buy one of these systems!

Tommyboy08

fclauson wrote: »

OK - but where with MHRV & super insulation the whole house levels at one temp over time

Definitely agree with you on this one, your just wasting money on all these unnecessary stats and controllers

KCross

fclauson wrote: »

OK - but where with MHRV & super insulation the whole house levels at one temp over time

Can you explain why that is?
If you have one room which is south facing with alot of glazing and another room north facing you are going to get temperature differences even with good insulation due to the thermal gain from the sun.
Even with HRV circulating the air you will still get differences throughout the day that the HRV will not compensate for that quickly.
-
Of course, if you have no stats the entire house is effectively an open zone to the heat pump so all rooms will be heated equally and then you will get one temp for the entire house.
-
My point was I did not want the heat pump heating the entire house when there are rooms I dont yet use and when I want the bedrooms a little colder than living areas.
-
I have HRV and the entire house is not at the same temp all over. Each room is at the temp that I have set it to so they are doing the job I want them to.
-
It is open to debate whether the extra cost of the stats are worth it but that depends on whether you want the control or not. For me it was the right one as I want that control and the stats are cheap anyway.

fclauson

ok - the temp may vary a bit - we leave most doors open all the time

The bedrooms should be a bit cooler but then our kids do homework in them so at the mo its not necessary to have them so

The HP is ruuning at about 10Kwh/day in the current weather for heating - that €2/day approx - so I think there is little to save by having the stats

sydthebeat

KCross wrote: »

Can you explain why that is?
If you have one room which is south facing with alot of glazing and another room north facing you are going to get temperature differences even with good insulation due to the thermal gain from the sun.
Even with HRV circulating the air you will still get differences throughout the day that the HRV will not compensate for that quickly.
-....

an intelligently designed house will allow these solar gains to be dispersed throughout the dwelling so that those rooms with low solar gains are not drawing off the heat source when there is over heating in other rooms.

Yes, there will be temp differences in the dwelling, dependent on user requirements. But its a badly designed house and heating system will have a burner heating a bedroom thats at 16 degrees when the living rooms is say 24 degrees.

if the difference are only 1 to 2 degrees the obviously the heat will transfer a lot more slowly.

fclauson

thats about it - the living space could be 22 or 23 on a nice day - the back bedroom may be 19 or 20

thats what I call sort of all at the same temp

KCross

fclauson wrote: »

thats about it - the living space could be 22 or 23 on a nice day - the back bedroom may be 19 or 20

thats what I call sort of all at the same temp

OK, then my house is all at the same temp based on that definition!

fclauson

compared to my mother in laws with her rayburn where is 150 deg C in the kitchen and sub zero elsewhere - you really have to think if you want to go "down the passage" as you might freeze before you get there :eek:

beyondpassive

muinteoir wrote: »

We are just about to make last decisions about our house. The house will be about 3200 sq ft doormer. It will have passive windows, well insulated, air tight membrane etc & solar panels. We have talked experts/ engineers/ plumbers/ architects but are still unsure. Should we go with-
Rads & Oil
UFH downstairs, rads upstairs, HRV, Oil condensed boiler
Or the above with geothermal instead of oil.

Would love to hear from experts/ someone who has built in the last few years. Were meeting builder in a week to decide!

Thanks.

Great discussion if I may get back to the OP.

A system to consider as option B, aside from heat pumps, is the more conventional hybrid system. Grid gas or LPG boiler and 2 banks of solar tubes feeding a heat bank or accumulator running underfloor downstairs and towel rads upstairs. MHRV. Heatmiser stats and Climote programmer.

Simple components that Joe plumber down the lane can maintain. The accunulator tank has plenty of spare inputs and outputs giving you the infrastructure to add more renewables or a heat pump when fossil fuel become prohibitive.

Certified

Some very good options and advice put forward. However, the most important thing you should do now if you have not done so already is get someone to calculate your homes overall heating demand and heat load. Without knowing that, you are really just guessing in the dark. Your build spec sounds very good so I would recommend running the design through the Phpp software.

If your house is near to the passive house standard (sounds like it could be) then your heat load and overall demand will be very low. Because your heating demand is maybe very low, if investing in a geothermal heat pump & underfloor heating or solar panels or even super fancy buffer tanks with triple internal zones with digital monitoring etc, you may never actually breakeven. It may be far simpler and cheaper just to use an electric immersion on night rate electricity. This is especially the case if you are going to use a long-term mortgage for finance?

In the case of the geothermal heat pump for example, the extra expense could realistically be €15,000. Even using the best value mortgage for a 30 year term will mean the system will actually cost you over €25,000. I would not be overly confident that the heat pump would outlive the mortgage either. The same goes for all the other stuff.

The obvious pain in the butt for energy efficient homes is the legal requirement of complying with Part L. Unfortunately for these buildings; many renewable energy systems will never give a return on the original investment. For example, for those availing of a mortgage, a €15,000 investment in the heat pump system will cost approx €70 every month for 360 months. For the year, that will be €840. The running costs will most likely be at least €250 a year on top of that, giving you an actual heating bill of €1,090. This figure is very far removed from €250!
The same house could be serviced by a small self-loading wood/wood pellet boiler for less than €500 a year. An electric immersion could do it for €720.
Assuming a 30year mortgage stays at the same interest rate as today and that both systems actually last the 30 years, also assuming that wood/wood pellets and electricity prices inflate at an equal rate then the heat pump will have cost the home owner €32,700. The simple wood/wood pellet system will have cost €15,000.

Some people will also add solar panels to avail of the free energy from the sun, on a house of 3,200 ft2 the home owner could be looking at another €6,000 added to the mortgage, which would actually cost another €330+ a year and at best €10,000 over the 30 years. A simple electric immersion on night rate could beat that.

In short, all I’m saying is that it takes a lot of calculations and discussion in order to select the correct heating system for a new home today. The most important being the heat demand and necessary heat load, every thing revolves around those figures. If your house turns out to need twice or three times the energy of a passive house for example then the sums may very well mean that a heat pump with solar panels or other would be the best way to go. Improving the specification of the building envelope would be cheaper however.

One thing that I find strange tho,

muinteoir wrote: »

We have talked experts/ engineers/ plumbers/ architects but are still unsure.

What did all the experts say? I assume they evaluated the building and gave you exact figures, a list of possible options and the system that they recommend which would meet all your requirements?

fclauson

good post - Part L is a pain - just be aware that even a PH will require heat - mine on the spread sheet needs 30ish Kwh/ day at this time of year - its actually using around 10kwh/day via a HP at present

BUT it definatly needs that heat - on days when its a bit dark and gloomy (the second of the two weather scenarios in PHPP) the house temp definatly drops and without the heating would definatly feel COLD :mad: on the days we lite the stove which helps

Condenser

Certified wrote: »

Some very good options and advice put forward. However, the most important thing you should do now if you have not done so already is get someone to calculate your homes overall heating demand and heat load. Without knowing that, you are really just guessing in the dark. Your build spec sounds very good so I would recommend running the design through the Phpp software.

If your house is near to the passive house standard (sounds like it could be) then your heat load and overall demand will be very low. Because your heating demand is maybe very low, if investing in a geothermal heat pump & underfloor heating or solar panels or even super fancy buffer tanks with triple internal zones with digital monitoring etc, you may never actually breakeven. It may be far simpler and cheaper just to use an electric immersion on night rate electricity. This is especially the case if you are going to use a long-term mortgage for finance?

In the case of the geothermal heat pump for example, the extra expense could realistically be €15,000. Even using the best value mortgage for a 30 year term will mean the system will actually cost you over €25,000. I would not be overly confident that the heat pump would outlive the mortgage either. The same goes for all the other stuff.

The obvious pain in the butt for energy efficient homes is the legal requirement of complying with Part L. Unfortunately for these buildings; many renewable energy systems will never give a return on the original investment. For example, for those availing of a mortgage, a €15,000 investment in the heat pump system will cost approx €70 every month for 360 months. For the year, that will be €840. The running costs will most likely be at least €250 a year on top of that, giving you an actual heating bill of €1,090. This figure is very far removed from €250!
The same house could be serviced by a small self-loading wood/wood pellet boiler for less than €500 a year. An electric immersion could do it for €720.
Assuming a 30year mortgage stays at the same interest rate as today and that both systems actually last the 30 years, also assuming that wood/wood pellets and electricity prices inflate at an equal rate then the heat pump will have cost the home owner €32,700. The simple wood/wood pellet system will have cost €15,000.

Some people will also add solar panels to avail of the free energy from the sun, on a house of 3,200 ft2 the home owner could be looking at another €6,000 added to the mortgage, which would actually cost another €330+ a year and at best €10,000 over the 30 years. A simple electric immersion on night rate could beat that.

In short, all I’m saying is that it takes a lot of calculations and discussion in order to select the correct heating system for a new home today. The most important being the heat demand and necessary heat load, every thing revolves around those figures. If your house turns out to need twice or three times the energy of a passive house for example then the sums may very well mean that a heat pump with solar panels or other would be the best way to go. Improving the specification of the building envelope would be cheaper however.

One thing that I find strange tho,

What did all the experts say? I assume they evaluated the building and gave you exact figures, a list of possible options and the system that they recommend which would meet all your requirements?

Couldn't agree less.
The difference in installation costs between a heat pump and a conventional system is more like €7,000 when you take the cost of the conventional system and solar panels required to comply minimally with part L.
Your assertion that a electric immersion could provide the same heat output for €720 that you can acheive with a heat pump is just plain wrong unless you assume the unit has a COP of less than 3 which even bad units will get close to.
You haven't factored in the rise in fuel costs over the next 10-15yrs where oil is currently inflating at over 3 times the rate of electricity and has been for a while.
Basicly payback on a good system would generally come between years four and six.

Going from an A3 to an A1 house is a case of massively diminishing returns. You have to invest so much additional money that if you invested the same into an A3 house and top class heat pump you would cover the cost of your build and your heating costs for the next 30yrs. Not to mention you could fit PV and pretty much run for free.

Certified

Condenser wrote: »

Couldn't agree less.
The difference in installation costs between a heat pump and a conventional system is more like €7,000 when you take the cost of the conventional system and solar panels required to comply minimally with part L.
Your assertion that a electric immersion could provide the same heat output for €720 that you can acheive with a heat pump is just plain wrong unless you assume the unit has a COP of less than 3 which even bad units will get close to.
You haven't factored in the rise in fuel costs over the next 10-15yrs where oil is currently inflating at over 3 times the rate of electricity and has been for a while.
Basicly payback on a good system would generally come between years four and six.

Going from an A3 to an A1 house is a case of massively diminishing returns. You have to invest so much additional money that if you invested the same into an A3 house and top class heat pump you would cover the cost of your build and your heating costs for the next 30yrs. Not to mention you could fit PV and pretty much run for free.

I think you may have misunderstood what I said?

KCross

Certified wrote: »

If your house is near to the passive house standard (sounds like it could be) then your heat load and overall demand will be very low. Because your heating demand is maybe very low, if investing in a geothermal heat pump & underfloor heating or solar panels or even super fancy buffer tanks with triple internal zones with digital monitoring etc, you may never actually breakeven. It may be far simpler and cheaper just to use an electric immersion on night rate electricity. This is especially the case if you are going to use a long-term mortgage for finance?

In the case of the geothermal heat pump for example, the extra expense could realistically be €15,000. Even using the best value mortgage for a 30 year term will mean the system will actually cost you over €25,000. I would not be overly confident that the heat pump would outlive the mortgage either. The same goes for all the other stuff.

The obvious pain in the butt for energy efficient homes is the legal requirement of complying with Part L. Unfortunately for these buildings; many renewable energy systems will never give a return on the original investment. For example, for those availing of a mortgage, a €15,000 investment in the heat pump system will cost approx €70 every month for 360 months. For the year, that will be €840. The running costs will most likely be at least €250 a year on top of that, giving you an actual heating bill of €1,090. This figure is very far removed from €250!
The same house could be serviced by a small self-loading wood/wood pellet boiler for less than €500 a year. An electric immersion could do it for €720.
Assuming a 30year mortgage stays at the same interest rate as today and that both systems actually last the 30 years, also assuming that wood/wood pellets and electricity prices inflate at an equal rate then the heat pump will have cost the home owner €32,700. The simple wood/wood pellet system will have cost €15,000.

Some people will also add solar panels to avail of the free energy from the sun, on a house of 3,200 ft2 the home owner could be looking at another €6,000 added to the mortgage, which would actually cost another €330+ a year and at best €10,000 over the 30 years. A simple electric immersion on night rate could beat that.

In short, all I’m saying is that it takes a lot of calculations and discussion in order to select the correct heating system for a new home today. The most important being the heat demand and necessary heat load, every thing revolves around those figures. If your house turns out to need twice or three times the energy of a passive house for example then the sums may very well mean that a heat pump with solar panels or other would be the best way to go. Improving the specification of the building envelope would be cheaper however.

One thing that I find strange tho,

What did all the experts say? I assume they evaluated the building and gave you exact figures, a list of possible options and the system that they recommend which would meet all your requirements?

An interesting response but I dont think the mortgage argument is a fair/balanced argument. Even using your immersion system you still have the mortgage to factor in and EVERY system, no matter how good, will have maintenance issues within the 30yr span of a mortgage.

A few other points.
You mention using an immersion on night rate electricity. That sounds fine but I presume at SOME stage there will be a call for heat during the day which will be expensive if the immersion is to provide it. Not sure a buffer tank would cover it all day particularly on very cold days?

You state:

Certified wrote: »

Unfortunately for these buildings; many renewable energy systems will never give a return on the original investment.

In that statement alone you have more or less ruled out all renewable energy systems as being some kind of rip off. Renewable energy isnt new. I presume the scandinavians, who have a much harsher climate than us, would have figured that out before we did!

You state:

Certified wrote: »

...assuming that wood/wood pellets and electricity prices inflate at an equal rate...

Big assumption there. One reason I didnt like the wood pellet route was that there isnt enough competition in the market and once you are into pellets you are hooked. If the price rises you cant do anything about it.
With electricity you can easily switch suppliers and as wind energy and PV get more affordable you should be able to offset your electricity costs. We are a few years away from that yet in Ireland but it will come.

It's a small point but electricity is also just more convenient. You wont run out of electricity and you dont have to order electricity.

You state:

Certified wrote: »

Some people will also add solar panels to avail of the free energy from the sun...

You dont need that if you have a HP. It will generate the hot water using all night rate electricity. It is quite cheap and would not justify spending €6k on solar.

You state:

Certified wrote: »

Improving the specification of the building envelope would be cheaper however.

I dont believe that is a true statement in all cases. As Condenser said, it is a case of diminishing returns so you would need to look at the figures before deciding that improving the spec is actually cheaper.

I'll agree on one thing you said...

Certified wrote: »

In short, all I’m saying is that it takes a lot of calculations and discussion in order to select the correct heating system for a new home today.

I am interested though to hear more about the immersion system you spoke of. You didnt give much detail on it.
How is it configured?
Is it driving under floor or rads or something else?
What kW is the immersion?
What size buffer tank would you need for, say, a 3000 sq ft passive house?
What are the initial purchase and install costs?
Do you have one in your house? What are your yearly running costs?

While I find your response interesting and it gives the reader another option to consider, there are a few gaping holes that need filling and some more specifics on the system you are recommending!

Certified

Guys just to confirm my position; I am not against renewable energy systems! My earlier post was simply to help illustrate to the OP that she needs to find out what her actual heat load and over all heat requirement is before choosing the heating system. Armed with that crucial information, only then in my opinion, can anyone in full confidence select or propose a heating system which best meets all the requirements for that proposed home and family.
In any case, not every decision is made purely on economic grounds. I have specified heat pumps in the past, not because they were the most affordable but because of the comfort and handiness of it. Every home is different and every family is different. I do not think there is a one solution fits all out there yet.

On the issue raised about it not being fair to introduce mortgage costs into the equation, I most certainly do think that on economic grounds it is an extremely important reality that must not be ignored.
If one system costs €15,000 or €7,000 more than another system, the additional burden of paying long term finance for it must be calculated. In my opinion it would be misleading a client if an energy consultant did not make the client aware of this indirect annual heating cost, especially as this part is so easy to calculate.

I was not proposing or recommending using only an electric immersion. I just gave an indication of the possible energy costs for the year for financial comparison reasons only. However, to expand on this system, the electric immersion simply heats a cheap as chips well insulated storage tank on night rate electricity, heat is drawn off it, if and when it is needed and distributed around the house via the MVHR system for free. The system would cost approx €2,500 supplied and fitted by a plumber. The direct annual heating cost is higher than for example a heat pump obviously but then the indirect heating costs are obviously lower.

How much do you reckon a geothermal heat pump and underfloor heating system would typically cost for supply and fit? I had given a figure of €15,000 in additional cost, however I may be a bit out?