Indicative manufacturer figures; AHHAC sizes and quotes to your heat-loss calculation and fuel access.
Choose the Immergas Magis if…
…you're building new or going all-electric, you want the lowest running cost (especially with solar), you want one system that also cools in summer, or you're pairing with underfloor and modern low-temperature radiators. Its 4–30 kW chassis range covers apartments through to large homes and light commercial.
→ Immergas Magis heat pumpChoose the Sime Brava Slim if…
…you already have mains gas, want the lowest upfront cost, need high flow temperatures for existing high-output radiators, or want fast, on-demand heat. The Brava Slim 30 BFR is a compact, quiet, NOx Class 5, 93.7%-efficient condensing boiler certified to AS/NZS 4552.
→ Sime Brava Slim 30 BFRTwo Italian approaches to the same job
Both the Immergas Magis and the Sime Brava Slim exist to do one thing — heat water for your hydronic system — but they get there completely differently. The Immergas Magis is an air-source heat pump: it extracts heat from the outside air and lifts it to a useful temperature using electricity, delivering three-to-four-and-a-half units of heat for every unit of power. The Sime Brava Slim burns natural gas or LPG and recovers the latent heat in the flue gases to reach up to 93.7% efficiency. One is all-electric and can run on your solar; the other is a proven, high-output combustion appliance. Immergas is distributed in Australia through Hunt Heating; Sime through Reece.
Running cost, cooling and hot water
On running cost the Magis usually wins — a COP of 3.5–4.5 beats a boiler capped near 94%, and on solar the daytime cost approaches zero. The Magis also cools: it reverses to circulate chilled water in summer, so one unit covers both seasons (Immergas mandates Adey MC Zero inhibitor on cooling installs, which we include as standard). The Sime is heating-only and needs a separate domestic-hot-water source, whereas the Magis can make hot water with a cylinder. Where the Sime shines is high-temperature output and upfront cost: for a gas-connected home with existing high-output radiators, a condensing boiler is often the pragmatic, lower-capital choice.
How AHHAC decides
Because we carry both, the recommendation follows your home — not our stock. We start with a heat-loss calculation, then weigh fuel access (no gas, or going all-electric → Magis), whether you want summer cooling (yes → only the Magis can), emitter type (low-temp underfloor → Magis; existing high-temp radiators → Sime), and upfront budget (tighter → Sime). For the underlying economics read our guide to electric boiler vs heat pump hydronic heating, compare the wider market on our Maxa vs Viessmann vs Immergas page, or see the same heat-pump-vs-boiler decision for the German brand on our Viessmann Vitocal vs Vitodens comparison. You can also explore all our hydronic heat pumps and hydronic boilers.
