Boiler and Heating Engineer in Denham
Heating Engineers in Denham
Local, Gas Safe registered boiler and heating engineer covering Denham and the surrounding area. Fixed prices, no call-out fee and a one year guarantee.
Information on this page last reviewed September 2026.
Gas Safe boiler and heating engineers in Denham
Denham is several places, and the boiler jobs differ between them. There is a historic village with three Grade I buildings, a run of later housing to the south of the river, a good many flats, and a canal-side edge near Uxbridge that has its own flood story. Home Comfort Assured is a Gas Safe registered heating firm based in Watford, number 586325, with no call-out fee. Boiler replacements, servicing and repairs are most of what we do, and the number is 07970 632 064.
What we do
Our services in Denham
Boiler repairs and servicing
Breakdowns, fault finding, annual servicing and replacement, on every major brand.
Read moreCentral heating
Radiators, valves, controls, power flushing and full system installation.
Read morePlumbing
Leaks and burst pipes, taps, cylinders, bathrooms and appliance installation.
Read moreUnderfloor heating
Design, installation and repair, wet systems in new builds and retrofits.
Read moreViessmann boilers
Why we are accredited, what the range does well, and how it compares.
Read moreLocal knowledge
Why Denham customers call us
Six places under one name
The council's 2008 appraisal lists the parish's main settlements as Denham Village, Denham Green, Higher Denham, New Denham, Tatling End and Willowbank. The conservation area covers only the historic core of the village.
30.7% of households in flats
In the Census area covering Denham, 30.7% of households live in purpose-built flats, against 16.7% across England and Wales, the highest of the five Buckinghamshire towns we work in. Flats have no permitted development rights, so a flue there is a planning question.
790 homes from 1955 to 1964
That is about 23% of the 3,450 properties in the Denham area, the largest band. Only 30 date from 1900 to 1918 and 40 from 1973 to 1982, and roughly a quarter were built from 2000, so it is a post-war and recent town with a historic village inside it.
285 and 283 mg/l
Affinity's postcode lookup put the UB9 postcodes we tried in two zones, Ickenham and Denham at 285 and Rickmansworth and Gerrards Cross at 283. Both are in Affinity's hard band, from a single 2025 sample each.
Three Grade I buildings
Denham Place, built 1688 to 1701, the church of St Mary and Savay Farm, a fourteenth century hall house, are all Grade I. The Denham Film Studios of 1936, by Walter Gropius and Maxwell Fry, are Grade II.
Colne Valley Park, not the Chilterns
The council's appraisal says the whole parish is in the Colne Valley Park, created in 1967. The Chilterns National Landscape, which does carry a flue rule, is several kilometres away on the government's planning data.
On the ground
Areas we cover in Denham
We cover UB9.
Denham Village
UB9The historic core along Village Road, where the council's appraisal says most of the listed buildings sit. The conservation area was re-designated with amended boundaries on 31 March 2006.
Denham Green
UB9Outside the conservation area. The council's flood assessment names Denham Green among places where sewerage capacity needs attention.
Higher Denham and Tatling End
UB9Higher Denham and Tatling End are settlements in the parish in their own right. The Colne Valley Park covers them, and so does the Green Belt, which is washed over them.
New Denham and Willowbank
UB9Between two channels of the River Colne near Uxbridge. A 2014 council investigation into flooding on Oxford Road and in Willowbank is about this end, not the village.
Not Denham: Harefield
UB9UB9 6 is Harefield, in the London Borough of Hillingdon, with a different council and different rules.
Which Denham
The council's 2008 appraisal for the Denham conservation area names six main settlements in the parish: Denham Village, Denham Green, Higher Denham, New Denham, Tatling End and Willowbank. The conservation area itself covers only the historic core of the village. The UB9 postcode district is wider than the parish, because it also takes in Harefield, which is in the London Borough of Hillingdon, and a few Uxbridge-ward addresses. Buckinghamshire Council, which took over from South Bucks District Council in 2020, is the planning authority for the parish and not for Harefield.
We ask for your road for that reason. The rules and the ground differ between the village, where Village Road is the spine of the listed buildings, and New Denham, which sits between two branches of the Colne.
A village inside a newer town
The council's historic assessment of Denham says that, despite being close to Greater London, the village has had only modest growth in the twentieth century, and that most development lies south of the Misbourne, away from the historic core. The figures agree. In the Census area covering Denham, the largest single band of property is 1955 to 1964 at 790 of 3,450, about 23%. Only 30 homes date from 1900 to 1918, and only 40 from 1973 to 1982. Roughly a quarter have gone up since 2000, derived from rounded Valuation Office figures. Council tax is weighted to the middle: bands C and D hold 730 and 960 of the 3,450, and 30% of homes are in bands F to H, the lowest share of the five towns we work in.
Housing type is where Denham differs most. 30.7% of households in that area live in purpose-built flats, against 16.7% across England and Wales, and only 30.0% in detached houses. The wider Census ward, which also includes Fulmer, has 25.6% in flats and 72 households in caravans or mobile homes, four times the national rate.
A boiler in a flat is a different job. Flats and maisonettes have no permitted development rights, so a flue is a planning matter from the start. There may be a freeholder or a managing agent, and the pipework is often shared. We would rather you asked the question early than found out halfway through.
The village: three Grade I buildings
Denham Place is Grade I, built in 1688 to 1701 for Sir Roger Hill. The church of St Mary is Grade I, with a Norman tower, and so is Savay Farm, described on its list entry as a fourteenth century hall house. Hills House and a wrought iron footbridge over the Colne are Grade II*. The Swan, the Falcon and the Green Man are Grade II, and so are Denham Film Studios, built in 1936 by Walter Gropius and Maxwell Fry for Alexander Korda.
The council's conservation area appraisal says the village was first designated in 1971 and re-designated with amended boundaries on 31 March 2006. Its leaflet for residents lists the works that need permission in a conservation area, and chimneys, flues and soil and vent pipes are not among them. Buckinghamshire Council publishes no flue wording of its own, and its current list of Article 4 directions has nothing in Denham. The national rule is what applies: in a conservation area, a flue on a wall or roof slope that fronts a highway and forms the principal or side elevation needs planning permission. If the house is listed, the test is whether the work affects its special character, and there is no blanket rule either way.
Historic England's advice on old chimneys applies to the village's oldest houses. Not every chimney can take a new liner, because flues in traditional buildings can be narrow, contorted or distorted by years of movement, and forcing a flexible liner down one risks damaging historic fabric. Better to know before a boiler is chosen than after.
Two zones, both hard
Affinity Water supplies Denham. Its own postcode lookup put five of the nine UB9 postcodes we sampled in the Ickenham and Denham zone, where the 2025 report gives 285 mg/l of total hardness, and four in the Rickmansworth and Gerrards Cross zone at 283. Each figure is one sample. They are 2 mg/l apart, so the two zones give essentially the same answer, and both fall in the 151 to 300 band Affinity calls hard. Scale settles wherever water is heated, and an annual service is how it is caught early.
Green belt, the Colne and the Chilterns
The whole parish is in the Colne Valley Park, created in 1967, according to the council's appraisal, which describes it as land to preserve for leisure, recreation and conservation. It is not the Chilterns National Landscape, which does carry a flue rule, and on an indicative postcode test in the government's planning data a Denham postcode sits several kilometres outside it. We found no flue rule attached to the Colne Valley Park.
The October 2020 draft of the neighbourhood plan, the text we read, describes the parish as entirely within the Green Belt, with Denham Green, New Denham and Willowbank inset and the village, Tatling End and Higher Denham washed over by it. That affects extensions, not boilers.
Water in New Denham
If your address is in New Denham or Willowbank, the council's report on the flooding of February 2014 is about you and not about the village. The River Colne overtopped its banks above Willowbank, flooded four properties internally along Oxford Road and external gardens and roads in Willowbank and Oakside, and the foul sewers overflowed as the local pumping station was overwhelmed. Homes behind the flood defences were not flooded inside. A later assessment says one of the five defence embankments was scored very poor on its last inspection, in 2022. None of that concerns a boiler in the village. In New Denham and Willowbank, plant below ground level is worth a question.
Who does the work
Andrew Millward has forty years in the trade, is a Heat Geek Elitist and is Viessmann accredited, and Elis Harizi does all our bathroom work. Every major make is welcome, Viessmann being the one we use most. We are gas engineers only. Around 77% of households in the Census ward heat with mains gas alone and 2.7% with oil, which is higher here partly because the ward includes Fulmer, but we do not work on oil or bottled gas.
Around Denham
Gerrards Cross is to the west, and Chalfont St Peter sits beyond it on the Misbourne. To the east, Northwood has its own page. The full range of heating work is on our heating page.
Tell us the road and what the boiler is doing: 07970 632 064, Andrew or Elis.
Need us in Denham?
Call and speak to the engineer who will do the work, or ask for a quote. No call-out fee, and a one year guarantee on what we do in Denham.
Step by step
Booking a heating engineer in Denham
Denham is several places and a lot of flats, so we start by asking what kind of home you have.
Ring and describe the problem
Call 07970 632 064 and tell us what the boiler is doing or what you want to replace. You speak to Andrew or Elis.
House, flat or something shared
We ask whether it is a house or a flat, and in a flat who owns the boiler and the pipework, because that decides who can agree to work and where a flue can go.
The road and the postcode
UB9 includes Harefield, which is a different borough, so the road matters. In the village we check the conservation area position before we talk about flues. There is no call-out fee.
The work
Andrew or Elis does the job.
Common questions
Which parts of UB9 do you cover?
The Denham ones. The UB9 postcode district also covers Harefield, which is in the London Borough of Hillingdon and so under a different council, and a handful of Uxbridge-ward addresses. Denham itself is a parish of several places: the village, Denham Green, Higher Denham, Tatling End, New Denham and Willowbank. Give us your road and we will say which one you are in.
Is the water in Denham hard?
Yes. Affinity Water's own postcode lookup split the nine UB9 postcodes we sampled between two zones, Ickenham and Denham at 285 mg/l and Rickmansworth and Gerrards Cross at 283, both from one sample in 2025. They are only 2 mg/l apart, so the answer is the same either way. Affinity's scale calls everything from 151 to 300 hard, and both figures sit in that band.
My boiler is in a flat. Are the flue rules different?
Yes. A house in a conservation area can normally put a flue on a wall or roof slope that does not face a highway without planning permission, but flats and maisonettes have no permitted development rights at all, so a flue is a planning question from the start. There are usually other people to consider too: who owns the boiler and the communal pipework, and who decides. Denham has more flats than any of the other Buckinghamshire towns we have looked at, so this comes up.
I live in the village conservation area. Can I change my flue?
The national rule applies: in a conservation area, a flue on a principal or side elevation that faces a highway needs planning permission. The council's 2008 conservation area leaflet for Denham lists the works that need permission and does not mention chimneys, flues or soil and vent pipes, and none of its current Article 4 directions covers Denham. Where a house is listed, the question is whether the work affects its special character.
Does the Colne Valley Park change anything for a boiler?
Not that we have found. The council's appraisal says the whole parish has been in the Colne Valley Park since 1967, created for leisure, recreation and conservation, but it is not the Chilterns National Landscape and we found no flue rule attached to it. The Chilterns designation, which does carry a flue rule, is several kilometres away on the government's planning data.
Are you Gas Safe registered?
Yes. Our number is 586325, the public register will show it, and our engineers carry ID.
Recent work nearby
See more of our work
What our customers say
See more reviews on TrustATraderElis has been fantastic and I would highly recommend him for any heating and boiler issues.
Elis is very professional, explaining exactly what he is going to do and then carrying it out. Supplied and fitted a replacement bathroom basin tap plus two isolation valves. Reliable and very pleasant. Top plumber and heating engineer.
True heating engineers are hard to find. Andrew is one of the few I have spoken with who is genuinely passionate about the industry, and does everything he can to steer it towards things like low temperature systems and weather compensation. His installation work itself is very tidy.
Meet your engineers
The engineers who turn up
Two engineers, both Gas Safe registered under registration 586325. When you book Home Comfort Assured, this is who does the work.
Andrew Millward
Founder and heating engineer
- 40+ years experience
- Heat Geek Elitist
- Viessmann accredited
Andrew has over 40 years in the trade and specialises in fault finding, boiler and heating repairs, and the design of energy efficient systems like heat pumps and underfloor heating.
Andrew on YouTube
Elis Harizi
Director and plumbing & heating engineer
- Plumbing since 2007
- Heat Geek member
- Gas qualified
Elis trained as a plumber in Greece in 2007, moved to England to gain his gas qualifications, and now designs and installs energy efficient heating as a Heat Geek member.
Got a job that needs sorting?
Call and speak to an engineer, or request a quote. No call-out fee, and we work across Hertfordshire and south Buckinghamshire.