This is the unit most North Alabama quotes lead with, so it gets the full receipts treatment: every number below comes from Generac’s own product page, cited in this page’s source comment. Headline first — the “22kW” is a propane rating. On natural gas, which is what in-city Huntsville and Madison homes will feed it, Generac rates the same machine at 21kW. Whether either number matches your house is a question for the Generac vs. Kohler breakdown only after you’ve matched the unit to your measured loads.
What does Generac publish for the 7042?
| Spec | Published figure |
|---|---|
| Output, natural gas | 21kW |
| Output, propane | 22kW |
| Engine | G-Force 1000, 999cc |
| Footprint | 48 × 25 × 29 in |
| Weight | 466 lb |
| Warranty | 5-year limited |
| NG draw, half / full load | 221 / 327 ft³/hr |
| Propane draw, half / full load | 2.53 / 3.71 gal/hr |
No prices here — installed cost turns on your specific fuel connection and panel, and unit-only retail moves too often to freeze. The rest of the brand table holds to the same sourcing rule: cited specs, no invented numbers.
Which home profile does it fit?
The single-system house — one central HVAC in the common residential tonnage range, gas appliances carrying some of the load, a panel without exotic 240V surprises. That’s the profile this tier was built to blanket, and with load management in the design it stretches to whole-home coverage for a large share of the homes in this market. The pass/fail specifics depend on your compressor’s starting amps and simultaneous loads, not on this page.
Who should look past it: dual-HVAC homes, all-electric homes, and anyone buying headroom for medical equipment. That’s the 26kW sibling’s territory — same footprint, more margin.
What does its fuel appetite mean at your house?
Here’s this page’s most useful verified fact: at half load, this unit draws a published 221 cubic feet of natural gas per hour. For scale, that’s a demand your meter serves on top of the furnace, water heater, and range — all possibly running during the same winter outage. If your meter’s delivery is marginal, this specific number is what makes the upgrade conversation concrete instead of theoretical.
On propane the same math turns into runtime: 2.53 gallons per hour at half load converts a 500-gallon tank’s roughly 400 usable gallons into about 158 hours — call it six and a half days of half-load running. That’s arithmetic on Generac’s figure, not a promise; heavier loads burn faster. But it’s the honest starting point for tank sizing, and it’s more than most sales conversations will show you on paper.
If those demands read like more machine than your outages justify, the portable-and-interlock route is the cheaper honesty.