Thermann installer, Melbourne’s south-east.

The Series 4 is Thermann's mid-tier — a real workhorse for VEU rebate customers where budget is tight but the outcome needs to be solid. R290 refrigerant, 5-year warranty, quiet enough for most yards.

Same platform as the 270 with a larger tank. Our recommendation when the household draw is over about 200 L/day.

The Series 5 steps up the compressor and controls over the Series 4. Better COP in cooler weather, longer warranty on the compressor. Worth the ~$400 step for anyone who wants more than the minimum.

The 315L Series 5 is our default recommendation in the Thermann range — best balance of tank size, compressor spec and price for a typical family draw.

The R290 variant of the Series 5 — tuned for cooler ambient temperatures. Not as extreme as Reclaim's CO₂, but a solid step above the standard Series 5 for anywhere the ranges hit single digits on winter mornings.

R290 Series 5 in the 315L tank size — the pick for a 4-5 person family in the Dandenong Ranges or a cool-morning postcode.

Solar hot water is a decreasing part of the market — heat pump usually beats it on economics and complexity now. But if you've got a good north roof and no PV, close-couple solar still works.

Split solar — panels on the roof, tank on the ground. Bigger tank capacity, no weight on the roof. More common for larger family homes than close-couple.

The 16 L/min is our smallest continuous-flow — enough for a couple or a small family with one bathroom. If you might ever run a shower and a tap simultaneously, jump up to the 20 L/min.

The 20 L/min is our most-installed continuous flow. Enough capacity for two showers simultaneously without pressure loss.

The 26 L/min handles two bathrooms running simultaneously plus a kitchen tap without pressure drop. Our default for family homes with more than one bathroom.

The 32 L/min is the biggest continuous flow we install — for homes with three bathrooms all running simultaneously or high-draw applications.

Gas storage is a shrinking market — most customers moving off gas move to heat pump. But for a like-for-like replacement where the existing gas connection and location can't accommodate anything else, this is the tank.

Electric storage doesn't qualify for VEU and is the most expensive fuel to run — we only install this as a last-resort emergency replacement. For any planned upgrade, the heat pump equivalent is a better financial outcome.