The 8 Models Compared
Sizing drives the selection. Most MA 2,000-3,000 sq ft single-families need 18-22 kW for whole-home backup. Larger homes or heavy electric load (heat pump + EV + central AC) need 22-26 kW.
| # | Model | kW | Fuel | ATS amps | Warranty |
|---|---|---|---|---|---|
| 1 | Generac Guardian 22 kW (7043) | 22 | NG/LP | 200A | 5yr / 2,000hr |
| 2 | Kohler 20RESCL | 20 | NG/LP | 200A | 5yr / 2,000hr |
| 3 | Generac Guardian 26 kW (7291) | 26 | NG/LP | 200A | 5yr / 2,000hr |
| 4 | Kohler 24RESCL | 24 | NG/LP | 200A | 5yr / 2,000hr |
| 5 | Cummins QuietConnect 20 kW | 20 | NG/LP | 200A | 5yr / 2,000hr |
| 6 | Generac Guardian 18 kW (7228) | 18 | NG/LP | 200A | 5yr / 2,000hr |
| 7 | Briggs & Stratton 20 kW | 20 | NG/LP | 200A | 4yr / 1,500hr |
| 8 | Champion 14 kW | 14 | NG/LP | 100A | 10yr (longer) |
Top 3 In Detail
Top 3 split between market leader (Generac), premium (Kohler), and the upsized Generac for larger homes:
#1 Generac Guardian 22 kW (Model 7043)
The MA market workhorse — Pro Build installs more of this single model than any other. 22 kW handles whole-home backup on most MA single-families including heat pump + EV charger. Air-cooled engine. Mobile Link WiFi monitoring (alerts for issues, exercise schedule). $5,500-$7,500 installed depending on fuel line + ATS work. Best for: most MA whole-home backups as the safe default.
#2 Kohler 20RESCL
Premium alternative to Generac. Liquid-cooled engine (vs air-cooled Generac) extends engine life and runs quieter. 20 kW sufficient for most MA homes. 5-year/2,000-hour warranty matches Generac. Best for: noise-sensitive locations (close to bedrooms) or buyers prioritizing premium build quality.
#3 Generac Guardian 26 kW (Model 7291)
Upsized Generac for whole-home electric load. 26 kW handles heat pump + EV charger + central AC + electric range simultaneously without load management. Best for: homes already fully or partially electrified, or planning electrification within 5 years.
Models #4-8: When Each Wins
The bottom 5 cover specific scenarios:
- #4 Kohler 24RESCL
- Upsized Kohler equivalent to Generac 26. Best for: larger Kohler-preference homes (4,000+ sq ft, multiple AC zones).
- #5 Cummins QuietConnect 20 kW
- Quietest in class (~60 dBA vs 65-70 typical). Best for: dense suburban lots where noise complaints from neighbors are a concern.
- #6 Generac Guardian 18 kW
- Smaller Generac for smaller homes. Best for: 1,500-2,000 sq ft homes without heat pump or EV charger; lower install cost than 22 kW.
- #7 Briggs & Stratton 20 kW
- Budget alternative to Generac/Kohler. Best for: budget-conscious installs where 4-year warranty is acceptable trade for $1,500-$2,500 lower cost.
- #8 Champion 14 kW
- Smallest whole-home option. 10-year warranty leads category. Best for: small condo/townhome installs where 14 kW + load management is adequate.
Massachusetts Permit + Installation Considerations
Generator install requires multiple trades and permits in MA:
- Gas line install: 248 CMR Gas Fitter License required. New gas line sizing + pressure test + utility coordination. $800-$1,800 typical.
- Electrical install: 527 CMR Master Electrician required. ATS install, panel/sub-panel work, grounding. $1,200-$2,500.
- NFPA 37 setback compliance: Minimum 5 ft from any opening (window, door, vent). 18-inch concrete pad. Air circulation clearance.
- Building/zoning permit: Most MA towns require building permit for generator install. Some towns (Newton, Brookline, Concord) have noise ordinances requiring specific generator locations.
- Utility coordination: Eversource, National Grid, or Unitil for natural gas line. Generator install can't proceed without confirmed gas service capacity.
- Inspection: Final inspection includes gas pressure test + electrical commissioning + ATS verification.
Frequently Asked Questions
What size generator do I need for my Massachusetts home?
1,500-2,000 sq ft single-family without heat pump or EV: 14-18 kW. 2,000-3,000 sq ft with central AC: 18-22 kW. Whole-home heat pump + central AC + EV charger: 22-26 kW. Heavy electric load (whole-home electrification): 26 kW. Manual J + electrical load calc determines exact sizing.
Natural gas or propane for a Massachusetts generator?
Natural gas when available — no fuel storage, no refill, runs indefinitely during multi-day outages. Propane in areas without NG service (rural Western MA, Cape Cod outer arm). Propane requires 250-500 gallon tank ($1,500-$3,000 install) and fuel delivery during outages.
How much does a whole-house generator install cost in MA?
$5,500-$11,500 for typical 18-22 kW Generac/Kohler installs. Includes generator, ATS, gas line work, electrical, permit, and inspection. Higher-end installs (24-26 kW, premium Kohler/Cummins, complex gas/electrical) reach $12K-$18K. Propane installs add $1,500-$3,000 for tank.
Does Mass Save offer rebates for whole-house generators?
No — Mass Save doesn't subsidize standby generators. The economic case is purely property protection (avoided food spoilage, frozen pipes, sump pump failure) and convenience. Generator installs do not qualify for IRC §25C federal credit either.
How loud is a generator during operation?
Air-cooled generators (most Generac, Kohler, Briggs & Stratton): 65-75 dBA at 23 feet — similar to a residential AC compressor at maximum. Liquid-cooled (Kohler 20RESCL, Cummins): 60-65 dBA — quieter. Cummins QuietConnect is the quietest at ~60 dBA. Sound enclosures available for noise-sensitive sites.
How often does a generator need to be exercised?
All standby generators self-exercise weekly (typically 5-15 minutes at low power). Annual service required by all warranties: oil change, filter, battery check, gas line inspection. $250-$450/year typical maintenance cost. Skipping service voids warranty.
Can I install a generator myself in Massachusetts?
No. Gas line work requires 248 CMR Gas Fitter License. Electrical/ATS work requires 527 CMR Master Electrician License. Permit pull requires licensed contractor. Civil penalties apply for unlicensed work. The components can be DIY-purchased but install must be licensed.
How long does generator installation take?
2-4 days typical for whole project. Day 1: pad install, generator placement. Day 2: gas line install + pressure test. Day 3: electrical/ATS install. Day 4: inspection + commissioning. Pre-install permitting takes 2-4 weeks before construction starts. Total project: 4-8 weeks from contract to commissioned generator.
References & Sources
- NFPA 37 Standard for Combustion Engines and Gas Turbines. https://www.nfpa.org/codes-and-standards/all-codes-and-standards/list-of-codes-and-standards/detail?code=37
- Massachusetts 248 CMR Plumbing and Gas Code. https://www.mass.gov/regulations/248-CMR-00000-uniform-state-plumbing-code
- Massachusetts Electrical Code 527 CMR. https://www.mass.gov/regulations/527-CMR-12-massachusetts-electrical-code-amendments
- Generac Guardian Series Specifications. https://www.generac.com/all-products/generators/home-backup-generators
