Gas with air to water

Dolantd

We have a 5000sq ft Georgian house, renovated last year. Ufh downstairs & rads upstairs, gas for heating and hot water. Fully dry lined. Double glazed, 450mm insulation in loft, 100mm insulation under 40mm screed for ufh. Gas proving to be v expensive for heat and hot water. What is my best option where I can use the gas as backup if required. I have option of solar or air to heat, all advise greatly appreciated

Calahonda52

Gas is as cheap as it gets so you need to look at heat and HW demand.
Why do u say its expensive for HW..?
What math have u to support this assertion. ?
What's the HW usage? Ie how many in house?
What height are ceilings?
Solar will set u back 5k or so.
Air to water, maybe 15k to 30k
So its time for some hard number crunching on life time costs, starting with the premise that solar does not make sense.

Dolantd

Monthly gas bil is €280-€350. Bi monthly electricity bill is €180
Usage is as follows
2 showers a day
2 baths per week for kids (all in there at same time)
Dishwasher 1 time a day
Ufh set at 19c, rads set at 17c.
Ufh running on stats so knocks off when temp reached
Rads on clock so only on 5 hours a day
?????

Dardania

Not being smart, but that square area is 454 square metres - which is quite a large space.

It seemd you have an excellent insulation standard (however don't know about heat losses due to windows, or air tightness...)

Maybe instead of putting a cheaper heat source in, the answer may be in how you use the heat i.e. system controls? Do you have zones? Are they set up correctly?

Also note that on the gas bill, if you work it out, a large proportion of the cost goes on taxes & standing charges etc. - no way related to consumption...

FrontDoor

Dolantd wrote: »

We have a 5000sq ft Georgian house, renovated last year. Ufh downstairs & rads upstairs, gas for heating and hot water. Fully dry lined. Double glazed, 450mm insulation in loft, 100mm insulation under 40mm screed for ufh. Gas proving to be v expensive for heat and hot water. What is my best option where I can use the gas as backup if required. I have option of solar or air to heat, all advise greatly appreciated

Is this a rural house? Have you access to timber?

Would one of those log gasification boilers make sense in this situation? I am not sure how compatible they are with UFH though.

sydthebeat

FrontDoor wrote: »

Is this a rural house? Have you access to timber?

Would one of those log gasification boilers make sense in this situation? I am not sure how compatible they are with UFH though.

its very compatable..... the gasification would heat a buffer tank (possibly 2000 litres) which the UFH would be supplied from, and it would also feed a HW cylinder for hot water.

Calahonda52

Tks.
Ceiling heights?
Where are room stats for rads, ie what height.
Re showers, we talking wet, wash, rinse showers or full 6 bsr pumped body jet jobbies?
As alluded to earlier replies.
Airtightness may be an issue.
Is site exposed?
Are wall vents sealed to plaster board and outside wall, ie no air gaps behind drylining?
How many recessed light fittings in ceilings.?
Have you draught lobby?
How well done is attic insulation?
Maybe air is passing under the insulation from one side to other.

Ufh beyond my paygrade but perhaps the boiler etc is set up wrong for dropping the temp for ufh.
What age is boiler, type, serviced?

Might be worth getting a blower door test

Dolantd

You certainly seem to know your stuff
We have insulated plasterboard, 50mm which is 2 inches away from old stone wall. there is a cavity there but all well stuffed with insulation at the openings.
Ceilings are 10ft high
Shower is a monsoon jobbie
Site is pretty exposed to wind
1 stat for all of upstairs
What is draught Lobby???
Attic has 450mm throughout

Calahonda52

Re You certainly seem to know your stuff.
Thank you. I am just standing on the shoulders of the other energy giants that stalk this forum
This is an iterative process.
One stat up stairs and all the rads on all the time when heating on?
Meant to ask earlier, how many open fireplaces?
Recessed lights?
Where is gas meter elec meter, phone boxes etc fitted?
They can be a hugh source of uncontrolled ventilation
Draught lobby is what planners call a porch.
The insulation around the wall vent holes I presume is glass fibre or rock wool or something similar.
It is not airtight so on an exposed site the wind will just pi $$ through it even if vent is shut and once its in behind the board it will just go every where.
I wrote elsewhere on this site as to how to make the junction properly airtight.
I presume vthevholes inbthe original walls are not sleeved?
If u cant find it pm me.
Sockets, lights switches tv points etc recessed into the drylining will also leak.
The insulted bosrd will do its job but my guess is u have massive uncontrolled ventilation.

A 10 foot ceiling is 25% more hot air required over the nirnsl 8 foot

gctest50

Dolantd wrote: »

We have a 5000sq ft Georgian house, renovated last year. Ufh downstairs & rads upstairs, gas for heating and hot water. Fully dry lined. Double glazed, 450mm insulation in loft, 100mm insulation under 40mm screed for ufh. Gas proving to be v expensive for heat and hot water. What is my best option where I can use the gas as backup if required. I have option of solar or air to heat, all advise greatly appreciated

might be a good idea to get in thermal camera and have a nose around,
if its leaking here and there it'll be needlessy expensive no matter how you heat it

have a look at the attached file :

Calahonda52

Or
http://flir.com/flirone/buy-eu.cfm
with your mobile fone.
They are selling very well, to such an extent that Flir are taking back older kit from their big customers and refurbing them and flogging them at reduced prices.

I know it will not be the same as a professionally preped survey using calibrated kit and a proper report but its worth considering if u know what to expect by researching on line and looking at Youtube etc
The red green blue etc temp ranges are relative as opposed to absolute.

Different materials have different emissivities so some care is needed but they do add value.