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Best generator install pros near Longmont, CO

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

Avatar for Absolute Electrical, Heating & Cooling, LLC
Absolute Electrical, Heating & Cooling, LLC
4.3(
328
)
Fixed Generator - Install

Serving Longmont, CO and surrounding areas

Approved

In business since 2013

Free estimates

Emergency services offered

"Absolute Electrical did a great job of installing our QuietCool fan. They were very professional, thoughtful (quietly closed front door as they went in and out) and cleanly (thoroughly cleaned work area). I would recommend them to any of our neighbors and friends."
Mini Split
Heated driveway
Furnace Inspection
Laying conduit for exterior electrical work
Electrical Panel Replacement

+34

Response time1 day
Recommended by91%of homeowners
Avatar for Just In Time Electrical Services
Just In Time Electrical Services
4.9(
32
)
Fixed Generator - InstallPortable Generator - Install

Serving Longmont, CO and surrounding areas

Approved

In business since 2019

Free estimates

Warranties offered

"Excellent experience, highly satisfied! Based on the 5 star reviews on Nextdoor, I called Just In Time Electrical to have some electrical issues fixed and new lighting added. Michael came out within a couple days to do an estimate and returned a couple days later to do the work. My home presented a few special challenges, but Michael and another technician, John, worked through them with patience and expertise, and they successfully completed all 3 projects with professionalism and to my specs. I am thrilled with the new living room recessed lighting, remote wall switch solution in another room, as well as the corrections made to my bathroom 3-way lighting. Thanks guys!"
Response time6 hrs
6 neighbors recently requested a quote
Recommended by86%of homeowners
Avatar for Precision Plumbing Heating Cooling Electric
Precision Plumbing Heating Cooling Electric
4.5(
198
)
Fixed Generator - Install

Serving Longmont, CO and surrounding areas

Approved

In business since 1982

Warranties offered

Credit card accepted

"Precision installed my water heater two years ago. When I had my furnace serviced, the technician checked the pressure on the water heater and it was very high, a component had failed. A plumber from Precision came out and replaced the defective part since it was under warranty. He suspected that a water pressure regulator may have to be installed but when he checked the water pressure coming into the house, it was in the acceptable range. He could have just as easily told me I needed this and it would have cost me $600 but Jacob was an honest man. I am so impressed with his integrity. I will use them again in the future for sure. The replacement of the defective part didn't cost me anything. Thank you Precision for being an honest company."
Response time6 days
16 neighbors recently requested a quote
Recommended by91%of homeowners
Avatar for DN Electric LTD
DN Electric LTD
5.0(
7
)
Portable Generator - Install

Serving Longmont, CO and surrounding areas

Approved

In business since 2025

Free estimates

Warranties offered

DN ELECTRIC LTD proudly serves its customers with pride, integrity and attention to the details that matter most to you. This is one of the many things that sets us apart from the rest. We are locally owned and operated. Give us a call today! \n

Electric
Basement receptacles
Basement receptacles
Basement receptacles
Basement receptacles

+1

10 neighbors recently requested a quote
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Generator Install FAQs, answered by experts

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.

In some situations, yes. Never try to put biofuel into any home generator without checking the specifics first. If a generator has the ability to run on diesel, it can also run pure biofuel (the clear kind made from seed oils, for example). But if you are using biofuel made from animal fats or vegetable oils, the generator will need significant modifications before it can handle a sludgier type of biofuel.

If you’re wondering whether gas generators produce carbon monoxide, know that natural gas generators do not produce carbon monoxide if they are functioning properly, as natural gas burns cleanly. However, if the generator malfunctions and the gas does not burn completely, there is potential for carbon dioxide to be produced. To prevent malfunctions, it's crucial to perform regular maintenance, including running the generator weekly and scheduling professional inspections every 6 to 12 months. Also, be sure to test your carbon monoxide detectors regularly to ensure they function in the rare case of the generator producing carbon monoxide.

Sizing a generator is a careful process that requires calculating the electrical load of your entire house. You have to take into account every device you want to use and their wattage requirements, plus the wattage needed to start them, and look for a generator that can safely run all that at around 80% capacity.

In more practical terms, a small home can run on a 10,000-watt generator (and if you only want to power a few key appliances, much less than that). A mid-sized home may need something between 15,000 and 22,000 watts. Larger homes require 25,000 watts or more. 

While the rating will tell you how many watts the refrigerator needs at the peak of its cycle, it requires additional wattage to start. At the bare minimum, you’ll need a 1,500-watt generator to get the fridge up and running after a blackout. A 2,000-watt generator should be sufficient for most home refrigerators.

The Longmont, CO homeowners’ guide to generator installs

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