Power: two big loads into the system you already run

The two loads, and why they behave differently

A sauna heater is resistive and beautifully predictable: it draws its rated power steadily until the thermostat cuts, with no inrush to speak of. The catch is size and duration — taking a well-insulated four-person cabin to 85 °C is forty to fifty minutes at full draw.

A chiller is the opposite: a modest continuous load with a compressor inrush at every start, spread across twenty-four hours, and the hours that matter are the ones after dark when an array is doing nothing. The lever there is the lid, which lets the tub coast overnight so the machine starts the morning where it finished.

Sequencing, in practice

The heater goes on a scheduled circuit, ideally inside the solar window where there is a meaningful array. The chiller is inhibited during the heater's heat-up and free to cycle afterwards. Neither can start within the same few seconds of the other, enforced in the controls rather than left to luck. Compressors get a soft start where the supply is marginal.

On a generator this matters more than capacity. A simultaneous start is what trips a set that would have carried both loads perfectly well one at a time.

The essential board, which people get wrong

Every property with a changeover has a division between what it feeds and what it does not, usually drawn when the building went up and rarely revisited when appliances were added.

We check that division physically before designing anything. We have found plunge circuits on the non-essential side more than once — meaning the one appliance that genuinely needs continuity was the one that lost it at every outage, and the owner concluded the chiller was faulty. The fix is a conversation with your electrician and a small amount of rework.

What we hand over, and what we will not do

You get two figures calculated from your system rather than a brochure: what a session costs, and what the chiller costs per month. Plus a load profile your electrician can read — peak draw, duty cycle, circuit allocation and what must never start alongside what.

We do not do the electrical work ourselves. We draw what the wellness loads need and hand it to a named licensed electrician who signs for it. And where the honest answer is that your system will not carry what you want, we say so and offer the alternatives rather than selling you a room that gets used twice.

In short

• Heater and chiller interlocked so they never start together
• Heater scheduled into the solar window where there is one
• Essential-board circuits verified physically, not assumed
• Session cost and monthly chiller cost calculated from your system