Borehole GSHP vs ASHP

porrige

Hi,

Building a new 260m2 house insulated as follows;
Walls 150mm
Floors 120mm (25mm at wall perimeters)
Ceiling 150mm
Windows 1.2u or less double glaze (triple on north elevation)
MHRVS
Provisional BER A2
Specified with ASHP for DHW & UFH

I’m guessing it’s not going to take much to heat this house and the heat will not escape so quickly if constructed accordingly.

Is it worth seriously considering a GSHP with Borehole ? Or would we be better spending money elsewhere or not at all ?

Thank you.
P

Condenser

porrige wrote: »

Hi,

Building a new 260m2 house insulated as follows;
Walls 150mm
Floors 120mm (25mm at wall perimeters)
Ceiling 150mm
Windows 1.2u or less double glaze (triple on north elevation)
MHRVS
Provisional BER A2
Specified with ASHP for DHW & UFH

I’m guessing it’s not going to take much to heat this house and the heat will not escape so quickly if constructed accordingly.

Is it worth seriously considering a GSHP with Borehole ? Or would we be better spending money elsewhere or not at all ?

Thank you.
P

The difference in cost will pay itself back multiple times in the lifetime of the system. It will be cheaper to run, have a longer lifespan, less parts to fail and be 100% dependable no matter what the weather. The cost difference is not as significant as many would have you believe either.

rolion

Hi,

Where is the location of your home ? Can you get gas ?
How many people living in it ?
What type of heating elements you have,radiators or under floor heating or both ?
Will you have some sort of heat storage ,will you plan to install later solar tubes or PVs ?

First choice will be geothermal if you can afford it,as per Condenser advise.

Good luck with the build...

porrige

rolion wrote: »

Hi,

Where is the location of your home ? Can you get gas ?
How many people living in it ?
What type of heating elements you have,radiators or under floor heating or both ?
Will you have some sort of heat storage ,will you plan to install later solar tubes or PVs ?

First choice will be geothermal if you can afford it,as per Condenser advise.

Good luck with the build...

Soil is fairly stoney, water drains away quickly
No gas
4 people
All UFH
No heat storage or plans for solar/wind

Thanks

porrige

Condenser wrote: »

The difference in cost will pay itself back multiple times in the lifetime of the system. It will be cheaper to run, have a longer lifespan, less parts to fail and be 100% dependable no matter what the weather. The cost difference is not as significant as many would have you believe either.

Thanks Condenser.
How is typical performance of borehole compared to ASHP at 10oC & above air temp?
What are the typical costs/considerations involved for borehole with GSHP ?

Calahonda52

porrige wrote: »

Hi,

Building a new 260m2 house insulated as follows;
Walls 150mm
Floors 120mm (25mm at wall perimeters)
Ceiling 150mm
Windows 1.2u or less double glaze (triple on north elevation)
MHRVS
Provisional BER A2
Specified with ASHP for DHW & UFH

I’m guessing it’s not going to take much to heat this house and the heat will not escape so quickly if constructed accordingly.

Is it worth seriously considering a GSHP with Borehole ? Or would we be better spending money elsewhere or not at all ?

Thank you.
P

While this could be ceiling between floors, if not then 150mm, IMO, is way too light, even if it meets regs
I specify 400 when using blown cellulose and it settles to about 375/350

Where will the MVHR system unit be located?

Condenser

porrige wrote: »

Thanks Condenser.
How is typical performance of borehole compared to ASHP at 10oC & above air temp?
What are the typical costs/considerations involved for borehole with GSHP ?

Generally a GSHP will be better than an ASHP all the way up to about 10C maybe even 12C air temp if fitted on the exact same heat distribution system. After 10C ASHP should be better but you're getting to the point of barely needing heat at that stage. It would have to be 15C outside before the performance advantage would be significant. The time to have an efficient heat pump is when the demand is largest.

On the house you described a 6 or 7kw GSHP would be sufficient. ASHP should be 30% larger to compensate for the drop in performance. A borehole if you needed to go for one would be about 3k for that size of machine but it'll last 100yrs. Your GSHP could last as much as 30.