Passive house Shepards hut ?

[Iceverge]

58 minutes ago, JohnMo said:

Going passivhaus on a small building isn't worth the effort as with some insulation heat costs are tiny. Not even sure a diesel heater is worth the effort, small storage heater, electric panel heater or a room through wall heat pump heater, sized at about 1+kW

 

I assumed there was no mains electric but a £10 fan heater would be fine if there was. 

 

I have a 2m mini office. Good airtightness, 0.23W/m²K walls and 1W/m² 2G doors and a 3G window.

dMEV.  Average U value of 0.35W/m²K. 

 

Once it's up to temp a couple of hundred Watts keeps it cosy. 

 

[saveasteading]

On 15/02/2026 at 23:58, Waterworks said:

sheperds hut for one person for all year round use 

I've maybe missed it but does this need planning permission? And then there is building control as it will be a habitation.

[Nickfromwales]

On 16/02/2026 at 11:14, JohnMo said:

Our summer house, is insulated, floor, roof and walls, double glazed wall with plenty of air leakage (rubbish design) and a dMEV fan. Insulation a country mile away from passivhaus, airtightness even further away.

 

Heating is by fan coil as an extension to the house UFH system (all run as single zone), ASHP flow temp set at 28.5 degs. Heating consumption for summer house is the best part of nothing much, as it piggy backed on to house and summer house is sitting at 19.5 degs most of the time. If we need additional heat we flick on an electric heater and it bumps it up to 21 in 30 to 40 mins.

 

Going passivhaus on a small building isn't worth the effort as with some insulation heat costs are tiny. Not even sure a diesel heater is worth the effort, small storage heater, electric panel heater or a room through wall heat pump heater, sized at about 1+kW.

No mains electricity  

[Nickfromwales]

On 15/02/2026 at 23:58, Waterworks said:

To go an alternative route to this question , if you were designing an off grid metal clad sheperds hut for one person for all year round use that will use the minimum of heating fuel how would you insulate it ? 

 

 

 

 

 

On 16/02/2026 at 07:31, Crofter said:

Floor: 300mm mineral wool

Walls: 150mm wool+ 50mm PIR

Warm pitched roof: 150mm wool+ 100mm PIR

 

Plus airtight membrane battened and taped.

 

Windows are 3G with u values of 1.0 or less.

👆. 
 

Airtightness is of paramount importance, eg more than just draught-proofing it.

 

I’ll not fret about the planning etc, thats another subject but i assume it’s in hand. A demountable building escapes these constraints as per @Crofter’s cabin / hut build. @Waterworks, have you read that thread yet?

 

This will need a portable genny and some solar PV, and probably a leisure battery as anyone staying there all year will need even basic cooking facilities and hot water / fridge etc??

 

Fridge and hot water can be done via propane, a-la a camper van, and ao could the heating. Gas is defo a major help here if it’s off grid and you need to be as least reliant on electricity as possible.

 

Going to need some power from somewhere unless you’re going full on Neanderthal. 

 

 

 

[sgt_woulds]

I've (tried) to sleep in a 6 man tent with one of these:

 

Outbacker® Pioneer Portable Tent Stove & Complete 2.41m Flue Kit | 2.5

 

Too hot even when there was only a flysheet as insulation.

 

I vaguely remember that the first 'eco' house built at the Centre For Alternative Technology was massivly over insulated (and poorly ventilated) back in the 90's (?) and inhabitants had to strip down to their underwear until the place was rebuilt.