Boiler Installation in Hertfordshire & London
We install high-efficiency boilers from leading brands with expert workmanship, honest advice and outstanding care.
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Gas Safe Registered Engineers Your safety is our priority.
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Up to 10 Year Manufacturer Guarantees Long-lasting protection on selected boilers.
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Honest Fixed Quotes Clear pricing with no hidden costs.
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Google Reviews4.9 out of 5
Based on 1,000+ reviews -
Gas Safe Registered Gas Safe Registered engineers for your peace of mind. -
Finance Available Spread the cost with flexible finance options.
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Local Experts Proudly serving Hertfordshire & London.
Our Complete Installation Process
From your initial quote to ongoing aftercare, we take care of everything.
1. Free Quote
Get a fast, fixed-price quote with no obligation.
2. Expert Installation
Our Gas Safe engineers install your boiler professionally.
3. Premium Boilers
We install high-efficiency boilers from leading brands.
4. Long Guarantees
Up to 10 years' guarantee for total peace of mind.
5. Aftercare
Ongoing support whenever you need us.
Which boiler is right for your home?
Different homes have different heating needs. Our guide helps you choose the perfect boiler.
Combination Boiler
(Combi)
Provides heating and hot water on demand without the need for a cylinder or tank.
- Ideal for small to medium homes
- Instant hot water on demand
- No separate hot water cylinder
- Compact, space-saving solution
- Energy efficient & cost effective
System Boiler
Works with a hot water cylinder to store hot water for your home.
- Perfect for homes with multiple bathrooms
- Excellent water pressure
- Hot water cylinder stores hot water
- More hot water outlets at once
- Ideal for medium to large homes
Conventional Boiler
(Regular or heat only)
Ideal for traditional heating systems with a loft tank and hot water cylinder.
- Best for older properties
- Works with existing pipework
- Loft tank stores cold water
- Great for larger homes
- Reliable & proven technology
Why Choose 1st Avenue Gas?
We're committed to delivering exceptional service and expert installations you can rely on.
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Gas Safe Registered All our engineers are fully qualified and Gas Safe registered.
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Fully Insured We're fully insured for your complete peace of mind. -
Experienced Engineers Years of experience installing and maintaining boilers across Hertfordshire & London.
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Fixed, Transparent Pricing Honest fixed quotes with no hidden costs or surprises. -
Manufacturer Approved Accredited installers for leading boiler brands including Worcester Bosch & Vaillant. -
Local Hertfordshire Experts Proudly serving homes across Hertfordshire, Bushey and London.
Boiler Brands We Install
We install and service boilers from all the leading manufacturers.
Recent Installations
Vaillant ecoTEC Plus 630 System Boiler
Bushey
10 year guarantee
Vaillant ecoFIT pure 825 Combination Boiler
North London
10 year guarantee
Vaillant ecoFIT pure 830 Combination Boiler
Harrow
10 year guarantee
Vaillant ecoFIT pure 800 Combination Boiler
Watford
10 year guarantee
Customer Reviews
View all reviews"Brilliant service from start to finish. The team were professional, clean and tidy, and the new boiler is working perfectly."
James R
St Albans, Hertfordshire
"Highly recommend 1st Avenue Gas. Honest pricing, great communication, and a top quality installation."
Sara T
Bushey, London
Spread the Cost of Your New Boiler
Flexible finance options available to help you get a new, energy-efficient boiler installed with affordable monthly payments.
Boiler Installation FAQs
How much does a new boiler installation cost?
A straightforward combi boiler installation typically costs between £1,900 and £3,200 fitted, depending on the make and model you choose and whether the flue, gas supply or pipework needs altering. A system boiler with an unvented cylinder for a larger home costs more. We give fixed written quotes after seeing the property — never a guess over the phone.
How long does a boiler installation take?
A like-for-like combi swap is usually completed in a single day. Moving the boiler to a new position, converting from a conventional system to a combi, or fitting a system boiler with a cylinder typically takes two to three days. We will confirm the timescale in writing before we start.
Which boiler brands do you install?
We install Worcester Bosch, Vaillant, Viessmann, Ideal, Baxi and other leading brands. As Vaillant Advance Installers we have direct manufacturer training and can offer extended warranties on Vaillant boilers. We will recommend what genuinely suits your home rather than whatever we happen to be pushing.
What size boiler do I need?
Boiler size depends on the number of radiators, bathrooms and occupants, not on the size of your house alone. An oversized boiler cycles inefficiently and an undersized one will not keep up. We carry out a proper heat loss calculation as part of every boiler installation quote.
Do I need a powerflush with a new boiler?
Often, yes. If your existing system has years of sludge in it, that debris will pass into the new boiler and can block the heat exchanger. Most manufacturers now require a clean system and a fitted filter for the warranty to remain valid. We will tell you honestly whether your system needs it.
Can I spread the cost of a new boiler?
Yes. We offer 0% APR finance over 12 or 24 months and low-rate finance over longer terms through Ideal4Finance, subject to status. See our finance page for the current options, or ask us when we quote.
Ready to upgrade your boiler?
Get your free, fixed-price quotation today.