help: what heating system?

Liberty__Belle

We are renovating a 1970s semi detached house and wondering what heat system to go with.

The house is 113sqm with a planned 24sqm extension.

We are planning insulation as follows:
fill cavity
dry line or external insulation
attic insulation
floor insulation
double (maybe triple glazed if its worth it) windows


We want to find the lowest cost heating system for this property and any advice is welcome

sinnerboy

That would be gas fired central heating

Liberty__Belle

Thanks sinnerboy. Appreciate that.

Is gas fuel the most energy efficient?
What about air to water? We have heard a lot about that lately.


Also, within the heating system I need advice on rads/underfloor heating or whatever we go with.

Fuschiarose

Hi have a supplementary question re heating systems and choice. New build 200msq on two floors. wish list is underfloor heating, triple glaze, 225mm insulated cavity plus as air tight as we can afford. Have been considering geothermal but not sure about the total dependency on electricity to run it.also read recently that running costs can rise if heat needs topping up.
Recently directed to Micro Chp heat & energy but difficult to get facts and figures. although noted thread on cost of calorgas.
Could see that whilst Chp system would lend itself to background constant heating. However if the house is properly insulated etc then the demand for heating during warm periods (the summer?) could be quite low. What is the pay back time for such systems?
Has anyone out there personal experience of these systems or know about them. would it be better to have an efficient oil fired boiler?

Liberty__Belle

Hi Fuciarose,

We have done a significant amount of research on this issue and we are still nowhere near "well informed".

However, what I have discovered is that in order for underfloor heating to run efficiently, you will also need a heat recovery system.

The reason for this is to avoid opening the windows for a "heat dump" - eg when cooking is taking place or, as you say, in warmer weather. By doing this, one has wasted a significant amount of energy and the thermostat will kick in trying to reheat the room.

A heat recovery system will redistribute the heat to colder areas and will allow ventilation into the room.

Personally, I love opening all the windows to allow the breeze rush through the house. Even during cold weather I do this (obv for a briefer period). It is not efficient to do this with underfloor heating as the most efficient way to run it is the have the room at a constant ambient temperature.

Not exactly answering your question but for us it was the deciding factor.

beyondpassive

Gas and solar thermal or heat pump and PV are the two top choices, you also need a buffer or accumulator tank to direct low grade heat to space heating. the renewables needs to provide about 20% of the energy. Delivery by underfloor with some towel rails and MHRV. Can be complicated with boiler stoves and discretionery heating radiators. Every client has different budgets and expectations of comfort and control. The starting point is to energy efficient design and clever compact use of space. Sounds easy on paper :-P

sinnerboy

Fuschiarose wrote: »

Recently directed to Micro Chp heat & energy but difficult to get facts and figures......

Micro chp is brand spanking new so no one will be able to report a sensible track record using it.

for a new house one can't answer "what heating system" in isolation. You must comply with Building Regulations Part L 2011 - Conservation of Energy. To do this the following information must be entered into a DEAP software analysis

your buildings unique measurements / orientation
all U Values
air tightness value
ventilation strategy
heating system
renewable energy provision

All the variables have to be "mixed correctly" in order to comply. What kind of heating system will depend on what values you have entered elsewhere in the programme.

Rushy Fields

Iknow i have been seeking advise on another thread but just thought that this thread might also help me.
I got a quote for solar to heat DHW and underfloor. €16k supply and fit. it does not include underfloor. It incorporates 10 panels 145 tubes a cylinder and a special patented unit. I dont know much about this system or any solar that can do both. They say i need a backup (Oil or Boiler stove) as it will provide 70% of my heating therefore i need a backup.
I also have a price for Geothermal (Horizontal Collectors) Heat pump COP 5.2 includes 500l tank and underfloor on both floors. This heats DHW and Central Heating. My house is 280m2
Can anyone tell me is the solar the way to go? or should i look at Geothermal or an alternative. My demand from the BER IS 56kWh/y

beyondpassive

Nealger, A heating system is exactly that 'a system', so its seen as a collective entity rather than a sum of individual component parts. Each component is affected by its interaction with all of the other components. Any low energy designer or mechanical engineer can only assess the suitability of a single piece of kit, when they know the others. They also need to know what are the boundary conditions or the demand of the building envelope itself, the clients subjective expectations of comfort, the project budget, method of procurement and compliance with Part L and renewable s obligation. Without that its wild guesswork.

Saying the above, but feck me thats a lot of solar, how big is the house? have you considered LPG instead of gas. What is your heat distribution and storage proposal. What is your ventilation system, what is your occupancy profile, hot water use profile....etc etc etc...?

Rushy Fields

beyondpassive wrote: »

Nealger, A heating system is exactly that 'a system', so its seen as a collective entity rather than a sum of individual component parts. Each component is affected by its interaction with all of the other components. Any low energy designer or mechanical engineer can only assess the suitability of a single piece of kit, when they know the others. They also need to know what are the boundary conditions or the demand of the building envelope itself, the clients subjective expectations of comfort, the project budget, method of procurement and compliance with Part L and renewable s obligation. Without that its wild guesswork.

Saying the above, but feck me thats a lot of solar, how big is the house? have you considered LPG instead of gas. What is your heat distribution and storage proposal. What is your ventilation system, what is your occupancy profile, hot water use profile....etc etc etc...?

BP: I have that information if it is of any use in someone helping me decide.
When you say Boundary Conditions can you tell me what do you mean. I can PM you the requirements etc.
Solar is going to be facing east also. The house is 280m2

Frank Black

Fuschiarose wrote: »

Hi have a supplementary question re heating systems and choice. New build 200msq on two floors. wish list is underfloor heating, triple glaze, 225mm insulated cavity plus as air tight as we can afford. Have been considering geothermal but not sure about the total dependency on electricity to run it.also read recently that running costs can rise if heat needs topping up.
Recently directed to Micro Chp heat & energy but difficult to get facts and figures. although noted thread on cost of calorgas.
Could see that whilst Chp system would lend itself to background constant heating. However if the house is properly insulated etc then the demand for heating during warm periods (the summer?) could be quite low. What is the pay back time for such systems?
Has anyone out there personal experience of these systems or know about them. would it be better to have an efficient oil fired boiler?

We've recently completed a new build house of approximately 240 sq m. We went with a geothermal and air recovery heating system.
The price for this system was about €25,000 (supplied and fitted) which included 2 no. 110m deep boreholes.
The system provides all hot water and heating needs.
The house was insulated to the latest building regulations as minimum, though I think we upped wall and roof insulation somewhat.
In terms of heating, it's brilliant. The house is at a constant temperature regardless of the outside ambient temperature - it's a bit disconcerting getting up in the moring and not having a clue what the weather is like outside until you look out the window. There is constant hot water on demand.
We probably haven't been in long enough to tell what out year round electricty bills are like - a friend of ours with a similar sized house and system claims €1,200 a year for his. The couple of bills we have received so far would tend to bear this out - if anything they are lower than expected, but we'll wait to see what it's like over the Christmas.
Compared to our old house (1980's 3 bed semi-detached), the amount we spend now is far less than what we would have spent on heating oil, coal/briquettes and electricty - and that house was less than half of the size of our new one.
PM me if you want contact details of the company we used - I would have no hesitation in recommending them.

beyondpassive

Boundary Conditions are whatever wraps around the heating system, in other words, your house. So what are the fabric U-Values, Window spec and orientation, ventilation type etc.

I'm just giving my experience in general, you should have a design team to help you get the best value and highest quality out of your build. Ask them.

Fuschiarose

Thanks everyone, really appreciating the replies. Finding it interesting and informative reading. I thought it was just me wandering around in this sea of information attempting to be green and frugal. It would appear that its not that easy to access the sort of recommendation and advice that people are looking for. It seems you can get quotes and advice for individual systems but not a comparison as to which might be best suited to your own situation. Even if it might be an efficient oil fired boiler.

Fuschiarose

Hi Black Francis, re your geothermal system. Were you recommended to a particular size of 'heat pump'? Did your friends electric bill include their domestic as well as their heating use?

Frank Black

Fuschiarose wrote: »

Hi Black Francis, re your geothermal system. Were you recommended to a particular size of 'heat pump'? Did your friends electric bill include their domestic as well as their heating use?

Sizing (and provision) of heat pump was carried out by the company we used and was presumably based on floor area of property.
Electricity Bill is for everything - heating, lighting, appliances, etc.

beyondpassive

Fuschiarose wrote: »

Thanks everyone, really appreciating the replies. Finding it interesting and informative reading. I thought it was just me wandering around in this sea of information attempting to be green and frugal. It would appear that its not that easy to access the sort of recommendation and advice that people are looking for. It seems you can get quotes and advice for individual systems but not a comparison as to which might be best suited to your own situation. Even if it might be an efficient oil fired boiler.

Well put FR, In reality once you get the Demand side right, it really dosen't matter what you heat your house with, any cost/benefit comparison would show that what you spent on the capital investment side, you recoup on running costs. What matters most is getting the design and integration right, getting a good plumber and having controls that are simple and functional.

gooner99

beyondpassive wrote: »

Nealger, A heating system is exactly that 'a system', so its seen as a collective entity rather than a sum of individual component parts. Each component is affected by its interaction with all of the other components. Any low energy designer or mechanical engineer can only assess the suitability of a single piece of kit, when they know the others. They also need to know what are the boundary conditions or the demand of the building envelope itself, the clients subjective expectations of comfort, the project budget, method of procurement and compliance with Part L and renewable s obligation. Without that its wild guesswork.

Saying the above, but feck me thats a lot of solar, how big is the house? have you considered LPG instead of gas. What is your heat distribution and storage proposal. What is your ventilation system, what is your occupancy profile, hot water use profile....etc etc etc...?

Is LPG not much more expensive than natural gas and even a bit more expensive that oil/kerosene?

beyondpassive

gooner99 wrote: »

Is LPG not much more expensive than natural gas and even a bit more expensive that oil/kerosene?

You wouldn't use LPG where you have grid gas. It's more expensive than oil per kWh but about the same when you factor in the efficiency of the boiler and the ability to use a modulating boiler. LPG is seen as being more cost stable than kerosene which is after all aircraft fuel.

gooner99

beyondpassive wrote: »

You wouldn't use LPG where you have grid gas. It's more expensive than oil per kWh but about the same when you factor in the efficiency of the boiler and the ability to use a modulating boiler. LPG is seen as being more cost stable than kerosene which is after all aircraft fuel.

Interesting.I only looked at the kwh on seai website a few months back and found it more expensive than heating oil.i had ruled it out on that basis,but now that it appears that it actually works out cheaper it warrants a closer look.is it as we'll suited to rads as oil is?

gooner99

beyondpassive wrote: »

You wouldn't use LPG where you have grid gas. It's more expensive than oil per kWh but about the same when you factor in the efficiency of the boiler and the ability to use a modulating boiler. LPG is seen as being more cost stable than kerosene which is after all aircraft fuel.

Had another look at the seai website and it's showing oil/kerosene at around 9.2 cent/kwh delivered and lpg at around 13 cent/kwh delivered. So I'm finding it hard to see how lpg works out cheaper than oil/kerosene?

beyondpassive

gooner99 wrote: »

Had another look at the seai website and it's showing oil/kerosene at around 9.2 cent/kwh delivered and lpg at around 13 cent/kwh delivered. So I'm finding it hard to see how lpg works out cheaper than oil/kerosene?

A litre of oil has 10kWh and a litre of LPG has only 7. Rental of the tanks shouldn't be included in the cost. Fuel inflation on oil is higher than gas.

It's about 11.5c per kWh for LPG. The SEAI calc's don't factor in the appliance use such as efficiency of the boiler, the warm up and the oversupply of heat, so yes, the oil is cheaper but not by 40% more like 15% and in 5 years that factor will be reversed.