Candia, NH Standby Generator Installation & Maintenance Guide

Estimated Read Time: 11 minutes

Choosing the right whole house generator size is not guesswork. Proper whole house generator sizing protects comfort, safety, and food during outages. In Southern New Hampshire, nor’easters and ice storms can cut power for days. This guide shows you how to match your home’s needs to the correct kW, step by step. You will see examples, fuel choices, and when to use load management. If you want a pro to confirm your numbers, our licensed team is ready to help.

Why Generator Size Matters in New Hampshire

Power events in NH are often weather driven. Nor’easters and ice storms can drop limbs and freeze lines. A correctly sized standby generator keeps the heat on, prevents frozen pipes, and protects medical devices. It also maintains lights, refrigeration, and internet for work and school.

Sizing is about two things:

1. What you want to power during an outage.
2. How much power those items need to start and run.

A unit that is too small trips, stalls, or forces tough choices. One that is too large wastes fuel and money. Proper sizing also protects sensitive electronics. Voltage dips from undersizing are hard on HVAC boards and refrigerators.

With Paul The Plumber, you get licensed and insured electricians who size for your priorities, local codes, and cold weather performance. We support gas, propane, and diesel units and service all makes and models.

How a Standby Generator and Transfer Switch Work

A standby generator is an automatic backup power system. When utility power fails, the automatic transfer switch detects the loss within seconds and shifts your home’s load to the generator. When power returns, it switches back and the generator cools down.

Key parts to consider during sizing:

• Generator kW rating: total available power.
• Automatic transfer switch: standard or load-shedding type.
• Fuel system: gas, propane, or diesel, with line size and pressure.
• Placement: outdoor pad with safe clearances and local code compliance.

The transfer switch choice matters for sizing. A load-shedding switch can manage large startup loads like central AC or well pumps. This lets a properly sized generator run a whole home without oversizing.

Step 1: Define What You Must Power

List must-haves first. Then add nice-to-haves. During sizing, we design for your must-haves and confirm if the nice-to-haves fit.

Common must-haves in NH homes:

• Furnace or boiler, circulator pumps, and thermostat
• Refrigerator and freezer
• Well pump or sump pump
• Lights in key rooms and exterior safety lighting
• Wi‑Fi, outlets for chargers, and a few outlets for work gear
• Medical equipment, if applicable

Nice-to-haves:

• Range or microwave for cooking
• Garage door opener
• Central AC or a ductless head for one floor
• Washer and gas dryer

Tip: Walk your home and note each item’s wattage. The appliance label or manual lists running watts and sometimes starting amps. If not, we can measure or estimate.

Step 2: Calculate Running and Starting Watts

Every motor has two wattage numbers:

• Running watts: the power a device needs while operating.
• Starting watts: the brief surge a motor needs to start.

Starting surges can be 2 to 3 times running watts. HVAC blowers, well pumps, and refrigerators all surge.

Quick method:

1. Add up running watts for all must-haves.
2. Add the largest starting surge among those items.
3. Add 15 to 20 percent headroom for cold starts and future needs.

Example scenario:

• Gas furnace blower: 600 running, 1200 starting
• Refrigerator: 200 running, 600 starting
• Sump pump: 800 running, 1600 starting
• Lights and outlets: 600 running
• Wi‑Fi and electronics: 200 running

Running total: 2400 watts. Largest surge: 1600 watts. Add headroom: about 20 percent. You land near 4.8 to 5.5 kW for this basic set. If you add a well pump or a ductless head, the size increases.

Step 3: Factor Fuel, Weather, and Site Conditions

Fuel type affects size, runtime, and maintenance.

• Natural gas: Unlimited supply if available. Check gas meter capacity and line size.
• Propane: Reliable in rural areas. Tank size sets runtime. Cold weather affects vaporization; larger tanks help.
• Diesel: Strong torque and common for larger systems. Needs on-site fuel storage and maintenance.

Cold weather reduces available output and increases starting loads. In New Hampshire winters, we size with extra margin. We also consider altitude, though most of Southern NH is near sea level.

Site considerations:

• Clearances from windows and doors
• Flood and snow drift risks
• Path for fuel lines and conduit
• Noise and neighbor setback rules

These details ensure your system performs during a storm, not just on paper.

Step 4: Pick the Right kW Range for Real Homes

Here are typical ranges we see in Southern NH. Your exact needs may differ.

• Essential circuits only, smaller homes or condos: 8 to 12 kW
• Most essentials plus a few convenience circuits: 13 to 16 kW
• Whole home with load management, common 2 to 3 ton AC: 18 to 22 kW
• Larger homes, multiple HVAC systems or deep well: 22 to 26+ kW

Two sample builds:

1. 1,600 sq ft home with gas heat, city water, and no central AC.
2. • Essentials list: furnace blower, refrigerator, lights, outlets, Wi‑Fi.
   • Recommended size: 10 to 14 kW, depending on also powering a microwave or sump pump.
2. 2,600 sq ft home with gas heat, 3-ton central AC, and a well pump.
3. • Essentials list plus AC and well pump with load shedding.
   • Recommended size: 18 to 22 kW with a smart transfer switch.

Load management lets a properly sized unit handle short surges by staggering starts. You get whole-home comfort without oversizing.

Step 5: Plan the Electrical and Gas Work

Proper installation protects your home and the generator. On installation day, our team prepares the outdoor pad, places the unit, runs the fuel lines, and installs the transfer switch and electrical connections. We pressure test fuel lines and verify gas meter capacity when needed.

Electrical planning items:

• Standard vs. service-rated transfer switch
• Load-shedding modules for AC, well, or range
• Subpanel vs. whole-home approach
• Surge protection for sensitive electronics

We coordinate siting with you for access, snow clearing, and aesthetics. Then we complete startup and teach you basic operation, including exercising and monitoring.

Permits, Codes, and Safety in NH

Generator work involves electrical and fuel systems. DIY mistakes can be dangerous. Our licensed electricians handle permits, inspections, and code compliance for your town. We follow manufacturer specs, NFPA fuel gas codes, and local utility guidelines.

Why this matters:

• Correct gas pressure prevents hard starts
• Proper wire size and grounding protect devices
• Clearances protect your family from exhaust risks
• Inspections document safe, professional work

Paul The Plumber provides 24/7 emergency service and fast response during storm season. We install across Derry, Nashua, Manchester, Londonderry, and nearby towns.

Cost, Value, and Warranty

Costs vary by size, fuel type, trenching, and switch complexity. Homeowners often budget for the generator, pad, gas work, electrical, and permits. We provide transparent, upfront pricing before work begins.

Value stack with Paul The Plumber:

• Licensed, background-checked electricians
• 2-year parts and labor warranty on our work
• 3-year parts and labor for Paul’s Promise Plan members
• Service for all makes and models

A standby generator protects your home’s value and comfort. It keeps heat, lights, refrigeration, and medical devices running when the grid goes down.

Maintenance: The Secret to Reliability

Most generator failures trace back to weak batteries, low fluids, or neglected filters. Prevent issues with simple routines.

Owner tips:

1. Exercise the unit weekly per manufacturer settings.
2. Keep the area clear of snow and debris.
3. Check the display for alerts monthly.

Pro maintenance typically includes:

• Battery test and replacement as needed
• Oil and filter changes at set hours or annually
• Coolant level checks and hose inspection
• Air filter and spark plug inspection
• Fuel line inspection and leak checks

Regular maintenance reduces repairs and protects your warranty. Our Paul’s Promise Plan adds priority service, extended warranty, and exclusive savings to keep your system ready.

Repair or Replace: How to Decide

Consider repair if the unit is newer, issues are minor, and parts are available. Consider replacement when:

• Frequent failures point to aging components
• Output is no longer enough for your home
• Repair costs exceed the value of the unit

Our licensed electricians diagnose the root cause, not just the symptom. We service gas, propane, and diesel generators and support all major brands. When replacement makes sense, we re-size based on your current loads and future plans.

Special Offers for NH Homeowners

• Save $250 on Generac generator install. Mention "$250 OFF GENERAC GENERATOR INSTALL" before 2025-12-31. Valid on standard pricing. One per household.
• Save $100 on generator installation. Mention "SAVE $100 GENERATOR INSTALLATION" before 2025-12-31. Valid on standard pricing. One per household.

Present the coupon at booking or before work begins. Call (603) 541-7986 to claim your savings.

Frequently Asked Questions

How do I estimate the right generator size for my home?

List your must-have circuits, total the running watts, add the largest starting surge, then add 15 to 20 percent headroom. A licensed pro can verify actual loads and fuel capacity.

What is the difference between running watts and starting watts?

Running watts keep an appliance operating. Starting watts are the short burst a motor needs to start. Pumps, refrigerators, and blowers often need 2 to 3 times their running watts to start.

Do I need a load-shedding transfer switch?

If you want whole-home coverage without oversizing, yes. A smart switch staggers big loads like AC or a well pump, so a right-sized generator handles surges.

Which fuel is best: natural gas, propane, or diesel?

Natural gas offers convenience if available. Propane fits rural homes and cold weather with the right tank size. Diesel suits larger systems. We size for fuel supply and cold-start performance.

How often should a standby generator be serviced?

Most systems need annual service or service by operating hours. Typical tasks include oil, filters, battery checks, and testing. Regular maintenance prevents many repairs and protects warranties.

The Bottom Line

Right-size your generator with a clear plan. Define essential circuits, calculate running and starting watts, and account for fuel and cold weather. For expert whole house generator sizing in Southern New Hampshire, Paul The Plumber delivers safe installation, strong warranties, and fast support.

Ready to Get Your Sizing Right?

Call (603) 541-7986 or schedule at https://www.paultheplumbernh.com/. Mention "$250 OFF GENERAC GENERATOR INSTALL" or "SAVE $100 GENERATOR INSTALLATION" to claim your discount before 2025-12-31. Protect your home before the next storm with a properly sized standby generator.

Get a free in-home generator sizing visit today. Call (603) 541-7986 or book online at https://www.paultheplumbernh.com/. Mention the active install coupons for savings.

About Paul The Plumber

Paul The Plumber provides licensed electrical and HVAC service across Southern New Hampshire. We deliver upfront pricing, 24/7 emergency support, and background-checked technicians. Our work is backed by a 2-year parts and labor warranty, or 3 years for Paul’s Promise Plan members. We are BBB A+ accredited and trusted by thousands of local homeowners. From generator sizing to safe installation and maintenance, we handle every step with care and compliance.