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Top-Rated Generator install pros in Grantham - Updated Nov 2026

Richard Hebert Master Electrician
5.0(
1
)
Fixed Generator - InstallPortable Generator - Install

Serving Grantham, NH and surrounding areas

Approved

In business since 2020

Credit card accepted

Offers commercial services

We can take on a wide range of residential and commercial electrical projects to include full installation for additions and remodels as well as wiring/panel upgrades, and a variety of other projects. We take pride in the quality of our work and our commitment to outstanding results. We look forward to building strong, long-term relationships with our clients and guarantee your satisfaction.

2 neighbors recently requested a quote
Levi Electric
New to Angi
Portable Generator - Repair

Serving Grantham, NH and surrounding areas

Approved

Free estimates

Emergency services offered

Warranties offered

Levi is a Master Electrician with over 10 years of experience in the electrical trade. He has primarily worked in high-end residential and custom homes, bringing strong expertise in electrical layout, lighting design, and coordination with insulation and building systems. Levi is highly knowledgeable in all aspects of residential electrical work, from rough-in to finish, and is committed to safe, code-compliant, and high-quality installations.

Avatar for UCS Construction and Design
UCS Construction and Design
New to Angi
Portable Generator - Repair

Serving Grantham, NH and surrounding areas

Approved

Free estimates

Emergency services offered

Warranties offered

We are new company just getting started I have a team of licensed professionals I work with. We are very well rounded in our field of work. Doing everything from small handyman repair and installation work to full remodels and renovations. No matter how big or small the job is we are here to help and give great prices and discounts to help home owners and other professionals. Always leaving up to code, quality work, and satisfied customers behind. We also do custom work such as Accent/feature walls that give a home that unique and elegant feel to it.

Avatar for JM Electric LLC
JM Electric LLC
4.5(
26
)
Fixed Generator - InstallFixed Generator - RepairGenerator - Install+4 more

Serving Grantham, NH and surrounding areas

In business since 1989

Free estimates

Emergency services offered

"The amount of work that needed to be done to our 1880 house was extensive. Joe listened to our needs and concerns and offered suggestions that improved our plans. His quote was very fair. He is easy to talk to, professional and honest. Caleb and Dylan who did the work were amazing to deal with. They were very knowledgable, worked hard, and were careful and patient dealing with the oddities of an old house. I highly recommend this company and will call on them for all my electrical needs."
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+15

Recommended by100%of homeowners
Avatar for Vermont Generator Systems
Vermont Generator Systems
5.0(
1
)
Fixed Generator - InstallFixed Generator - RepairGenerator - Install+4 more

Serving Grantham, NH and surrounding areas

In business since 2008

Free estimates

Emergency services offered

Since 2004, Vermont Generator Systems has proudly supported the backup power needs of homes and businesses across parts of Vermont and New Hampshire. Our experienced team is with you every step of the way, from the initial site assessment to professional installation and ongoing maintenance. VGS has deep expertise in installing and servicing Generac generator systems.

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Response time6 hrs
Response rate100%
NH Generator Installers, Inc.
New to Angi
Fixed Generator - InstallGenerator - Install - For BusinessPortable Generator - Install

Serving Grantham, NH and surrounding areas

In business since 2009

Free estimates

Credit card accepted

About NH Generator Installers (formerly Corr & Son's Electric) - Concord, NH \n \nNH Generator Installers is a team of motivated team members dedicated to providing top-quality power generator installations at competitive prices, including home generators and commercial electric generators. We are a professional, reliable, hard working generator distribution and installation company that takes pride in completing all jobs accurately and in a timely manner. \n \nWe are committed to establishing long lasting relationships with our customers by exceeding expectations, gaining trust through exceptional performance, unparalleled service, and honest and ethical business practices. We recognize that teamwork is essential in order to achieve successful project completion. \n

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Generator Install FAQs, answered by experts

These advanced generators use a key fob or a smartphone app to remotely start, which is ideal for getting power back on immediately without venturing outside. This feature is more common on whole home generators, but you may be able to find it on large portable generators, too.

A home that is 2,500 square feet will likely need a 20kW to 25kW generator. Consult your local generator installer to confirm the generator size needed to power your home before purchasing a new one. Be sure to consider how much power your necessary devices need to run.

Generators are safe to use as long as they are installed and operated correctly according to the manufacturer's recommendations. The most critical safety tips are to never use a portable or fuel-powered generator inside an enclosed space due to the risk of lethal carbon monoxide poisoning; always operate it outdoors where fumes can dissipate away from your home. Additionally, never attempt to connect a generator to your home’s electrical panel yourself—hire a professional to ensure the setup meets safety standards. Finally, avoid overloading the generator by not connecting more appliances than it is rated for, as this can damage your equipment or cause a fire.

To determine the right size generator for your house, you should calculate the total wattage of the appliances and devices you want to power during an outage. List all essential items, note their start-up wattages, and add them together.

Here are some typical wattage requirements for common appliances:

  • Refrigerator: 600 watts

  • Large dehumidifier: 700 watts

  • Large window air conditioner: 1,400 watts

  • Water heater: 3,000 to 4,500 watts

  • Electric furnace: 5,000 to 25,000 watts

A 7,500-watt generator might be sufficient for essentials like a refrigerator, freezer, well pump, and lighting circuits. However, for high-demand items like a water heater or furnace, a whole-home generator is a better choice. A portable generator may be enough if you only need to power a few critical items.

While home square footage can offer a rough estimate, it is not always a reliable indicator. For reference, here are some typical generator sizes based on square footage:

  • 1,000 sq ft: 6–9 kW

  • 1,500 sq ft: 7–10 kW

  • 2,000 sq ft: 10–14 kW

  • 2,500 sq ft: 12–16 kW

  • 3,000 sq ft: 16–20 kW+

For the most accurate sizing, consult a professional who can calculate your home's peak and average power consumption and recommend the optimal generator.

Generators run on a variety of fuel types, ranging from natural gas to solar power. Keep in mind that fuel costs varying by type:

  • Natural gas: $2,000–$21,000 per year 

  • Liquid propane: $2,000–$21,000 per year

  • Diesel: $3,000–$20,000 per year

  • Gasoline: $500–$3,000 per year

  • Solar generator: $2,000–$25,000 per unit

  • Battery backup: $10,000–$25,000 per unit

The Grantham, NH homeowners’ guide to generator installs

From average costs to expert advice, get all the answers you need to get your job done.