Hi

Trying to decide how to heat my house - currently building an extension - turning my 2 bed bungalow into a 5 bed house + a few other rooms

I would like a system that works well, efficient and relatively cheap to install.

The options as I see it are

Radiators (Victorian)
- MUST be inefficient having to heat the water that hot to try any get a bit of convection going?
- however current system uses Rads
- would be the path of least resistance

Wet under floor heating (80's)
- Must be more efficient than Rads - lots of pipes
- would my existing boiler (Valient Combi) work effectively with it (I assume it was not designed to produce lots of low temperature water)
- Its slow to respond to temperature changes?
- Any places I can get further installation info ?
- Could I use the return water (lower temp) from the current Rad system to heat the extension (at least until I can mod the rest of the house)
- Using relatively low temperature heat _ could I supplement the heat source at a later date i.e. solar, wind, waste water recovery etc?

Hot air system (21st Century)
- What I can gather from my cousin who uses these systems to heat swimming pool buildings _ is that they are stunningly fast to respond?
- have a void under my bungalow and extension so could install ducting
- Should be efficent because of the lower temperature?
- What about condensation / humidity?
- Could I use the return water (lower temp) from the current Rad system to heat the extension (at least until I can mod the rest of the house)
- Using relatively low temperature heat _ could I supplement the heat source at a later date i.e. solar, wind, waste water recovery, wife running on a tread mill, etc?

Thank you

Cameron