Solar, Batteries And All-Electric Dwellings

An all-electric dwelling with rooftop solar and battery storage is a specification decision with construction consequences, and most of those consequences land before the module leaves the factory.

Why it is easier in a factory

Every cable route, every penetration and every mounting point is decided while the wall is open.

Running a cable through a stud wall on a factory line, before the lining goes on, takes minutes. Running the same cable in a finished dwelling means opening the wall, chasing it, repairing it and painting it.

Which means the practical question is not whether it can be done. It is whether the decision is made in time.

What has to be resolved before fabrication

**Roof orientation and array position.** Which roof planes carry panels, how many, and where the mounting points sit relative to the structure underneath. On a factory-built roof those fixings can be structural rather than surface-mounted.

**Cable routes from the array to the inverter,** with no penetration added later through a completed waterproof roof. Every penetration through a roof is a future leak unless it is designed, and designing it is what keeps the [waterproofing](/blog/waterproofing-in-a-factory-built-building) intact.

**Inverter and battery location.** Both need ventilation, both have clearance requirements, both are heavy, and a battery has its own separation and fire requirements. Where they sit changes the wall behind them.

**Switchboard capacity.** An all-electric dwelling with induction cooking, a heat pump hot water system, reverse-cycle conditioning and vehicle charging draws more than a gas-supplemented one. The board and the incoming supply are sized for it at design, not discovered at connection.

**Vehicle charging,** even if it is not installed on day one. A conduit and a spare circuit cost very little in the factory and a great deal later.

The load side matters more than the generation side

Adding panels to a dwelling that loses heat is buying energy to waste.

So the sequence runs the other way: get the building fabric right first, then size the systems to what the dwelling actually needs.

That means the insulation, the glazing, the thermal breaks and the sealing, which is the substance of [thermal performance in a factory build](/blog/energy-and-thermal-performance-in-modular). A factory-built envelope is sealed to a tolerance a site-built one struggles to match, and that is where most of the saving comes from.

Then the appliances. A heat pump hot water system, a properly sized reverse-cycle system and induction cooking together change the consumption profile more than a larger array does.

In accessible housing

There are specific reasons this matters more in a Specialist Disability Accommodation dwelling.

**Running costs fall on the resident.** Many residents are on a fixed income, and a dwelling that costs less to run is a direct and permanent benefit.

**Thermal comfort is not optional.** A resident who cannot easily adjust their own clothing, move to another room, or leave the dwelling depends on the conditioning working. That raises the consequence of a system failure.

**Backup matters more.** Where a resident relies on powered equipment, a battery is not a convenience. The design implications of that are worth working through explicitly rather than assuming.

Monitoring and control

Whatever is installed needs to be usable by the person living there and by whoever supports them.

Which frequently means simple physical controls at an accessible height alongside the app, rather than an app instead of controls. A system that only works through a phone excludes some of the people the dwelling was built for.

The honest position

Solar and storage do not make a poorly designed dwelling efficient. They make an efficient dwelling cheap to run.

Built in the right order, and resolved before the module is closed up, an all-electric factory-built dwelling is straightforward. Reversed, it becomes a retrofit on a building that was finished six months ago.

Discuss a project.

MADEmodular / MADEbetter.