Air to water heat

Air to water virgin

Hi all my wife and I are starting our journey building our first home . We are just after applying for planning.
We are looking for advice on air to water heat . We are going for underfloor heating option no radiators.
We are wondering is a the air to water sufficient or should we use a dual system and run gas or oil also ?
What happens when temperatures are bellow zero how effective is it as a stand alone system ?

agusta

Air to water virgin wrote: »

Hi all my wife and I are starting our journey building our first home . We are just after applying for planning.
We are looking for advice on air to water heat . We are going for underfloor heating option no radiators.
We are wondering is a the air to water sufficient or should we use a dual system and run gas or oil also ?
What happens when temperatures are bellow zero how effective is it as a stand alone system ?

Yes the air to water is sufficient on its own. it has a back up heater element if temperatures are very low.

Water John

Yes, you can get a dual one. It produces water at two heat levels. One for the UFH and a higher temp separate level. This is because the higher temp is less efficient and thus kept as small as possible.
Good quality A2W can run in climates colder than ours.
Above all, focus on insulation and a sealed envelope. If you do this, your heating bill will be very low. Have a look also at Mechanical Heat Ventilation Recovery (MHVR). This basically takes air out of the house and uses it to heat fresh air going into the house. Necessary in modern houses IMO. Cost about €5K, but very low running cost.

cruiser202006

Air to water is more than sufficient. Decent units will heat without back up immersion down to around -15 degrees which we rarely see

Air to water virgin wrote: »

Hi all my wife and I are starting our journey building our first home . We are just after applying for planning.
We are looking for advice on air to water heat . We are going for underfloor heating option no radiators.
We are wondering is a the air to water sufficient or should we use a dual system and run gas or oil also ?
What happens when temperatures are bellow zero how effective is it as a stand alone system ?

Air to water virgin

Water John wrote: »

Yes, you can get a dual one. It produces water at two heat levels. One for the UFH and a higher temp separate level. This is because the higher temp is less efficient and thus kept as small as possible.
Good quality A2W can run in climates colder than ours.
Above all, focus on insulation and a sealed envelope. If you do this, your heating bill will be very low. Have a look also at Mechanical Heat Ventilation Recovery (MHVR). This basically takes air out of the house and uses it to heat fresh air going into the house. Necessary in modern houses IMO. Cost about €5K, but very low running cost.

We will be trying to keep our costs as low as possible for this build. Our main focus will be insulation ,Windows/doors and heating making the house as energy efficient as possible . I know a guy who has the heat recovery unit and he swears by it .
Would you recommend a dual heating system combining air to water and heat recovery .
The guy I know has geothermal and the heat recovery he doesnt rate the geo at all I don't know why but he keeps saying stay away from it never gives a reason just totally against it .

Water John

Geo is dearer. Has a bit higher efficiency but that depends on installation and subsoil. I would go with A2W. The MHRV is a separate system. I would put it into modern houses as you will basically have a 'sick house', stale air and mouldy, as you won't have enough air changes.
So 2 stage A2W and a MHRV system. All heating and hot water, sorted. Very low annual running cost. Put in a dry stove as a feature, possibly. Handy back up for electrical failure.

Air to water virgin

Water John wrote: »

Geo is dearer. Has a bit higher efficiency but that depends on installation and subsoil. I would go with A2W. The MHRV is a separate system. I would put it into modern houses as you will basically have a 'sick house', stale air and mouldy, as you won't have enough air changes.
So 2 stage A2W and a MHRV system. All heating and hot water, sorted. Very low annual running cost. Put in a dry stove as a feature, possibly. Handy back up for electrical failure.

So the MHRV will give me the air changes required to remove all the stagnent air ?
Another issue that might arise with the A2W is we will bu using a well for water I believe this is not ideal , can you shed any light on this ?

Water John

Others may know better but I think you can use a stainless steel exchanger, if the water is acidy, or has high lime, iron or manganese.

EHP

Just a taught and wondering what others think, if building a new house with the highest levels of insulation and air tightness is there enough heat demand to justify a cheap to run system that was expensive to install first day. What would be the price difference between installing air to water and an oil boiler and would the running cost not be low with either system if properly insulated.

exaisle

Water John wrote: »

Others may know better but I think you can use a stainless steel exchanger, if the water is acidy, or has high lime, iron or manganese.

I run an A2W and MHRV (with the added benefit of a solar panel which preheats water used for domestic purposes in the winter and supplies all the DHW for the rest of the year) and my well water is acidic with iron and manganese. I have filters installed to correct this and have no problems. I just need to check the filters annually to ensure that there's sufficient filter medium to do the job adequately.

I'm wondering if OP has had their water tested?

OP- if your well water is usable as is, then there's no reason why you should have a problem.

cruiser202006

There’d be a big difference between heat pump and oil boiler. But you couldn’t just install an oil boiler you’d need to install a solar as well which would prob even things up

EHP wrote: »

Just a taught and wondering what others think, if building a new house with the highest levels of insulation and air tightness is there enough heat demand to justify a cheap to run system that was expensive to install first day. What would be the price difference between installing air to water and an oil boiler and would the running cost not be low with either system if properly insulated.

day dreamer

I don't want to put a dampner because planning a house is very exciting

I'd wait until you have planning permission granted. Until this is in the bag you are wasting time and energy. You'll have plenty of time then to sort out heating then. I've had 3 failed attempts before success.

New building regulations mean you nearly have to put in air to water or geo thermal unless you are on mains gas. Very difficult to get A rating with oil boiler.You can always opt out of the building regs either

Spending a lot on insulation, air tightness, triple glazing, heat recovery etc is crucial and is expensive but its what you'll have to do if you want to heat house cheaply.

Good luck

cruiser202006

day dreamer wrote: »

I don't want to put a dampner because planning a house is very exciting

I'd wait until you have planning permission granted. Until this is in the bag you are wasting time and energy. You'll have plenty of time then to sort out heating then. I've had 3 failed attempts before success.

New building regulations mean you nearly have to put in air to water or geo thermal unless you are on mains gas. Very difficult to get A rating with oil boiler.You can always opt out of the building regs either

Spending a lot on insulation, air tightness, triple glazing, heat recovery etc is crucial and is expensive but its what you'll have to do if you want to heat house cheaply.

Good luck

Oil boilers are a rated boilers the same as mains gas boilers are so what you say makes no sense. Going with gas or oil means would still need a renewable source wether it be solar thermal or pv.
As for part l there is no opt out on building regulations, can only opt out on certification.