Heating
Oil and LPG
Air conditioning and plumbing
Get my boiler priceGas and LPG, an estimate online 
Heating / Cooling / Plumbing
Andover, Salisbury, Winchester, Romsey & surrounding areas
New boilers, air conditioning, servicing, repairs and plumbing from Dexter Whittaker-McGreal. Gas, LPG and oil, across Hampshire and Wiltshire.
Gas and LPG work by a Gas Safe registered engineer, and oil work under OFTEC. Ask to see the card when Dexter arrives.
Dexter Whittaker-McGreal, based in Andover and covering Salisbury, Winchester, Romsey and the villages between. Not a call centre.
See an estimated, fitted price for a new boiler or air conditioning before anyone visits. Dexter confirms the final price before work starts.
New boilers and air conditioning are priced online. Servicing, repairs and plumbing are booked straight in, with the price agreed first.
A new gas or LPG boiler, sized to your home and fitted by Dexter. Choose from Ideal, Vaillant and Worcester Bosch and see an estimated, fitted price online before anyone visits. Combi, system and regular boilers are all covered.
From £2,863fitted, including VAT
Wall-mounted air to air units that cool a room in summer and heat it in winter. Each system is designed room by room, with the indoor and outdoor units sized for the space, and the price tool gives an estimated price for the whole installation.
From £2,042a room, fitted
A yearly service keeps your boiler safe and running efficiently, and most manufacturers require one to keep the warranty valid. Dexter tests the combustion with a flue gas analyser, checks the safety devices and pressures, and tells you plainly if anything needs attention.
From £85
No heating, no hot water, a leak or a fault code on the display. Dexter finds the cause, explains it in plain English and agrees the price with you before any work starts.
From £90call-out + first hour
Oil boilers OFTEC registered. New oil boilers, servicing and repairs, priced after a quick chat or a photo. Find out more → 
LPG boilers On bottled or tank LPG? The same price as mains gas, from £2,863 fitted. Find out more → 
Combi conversions Loft tanks and cylinder out, a combi in. The job Dexter does most, from £3,513. Find out more → 
Hot water cylinders Unvented cylinders for strong showers, or a like for like swap for a tired old tank. Find out more → 
Radiators and valves New column, designer and like for like radiators, and thermostatic valves. Find out more → 
Power flushing Sludge cleared out of the system to fix cold spots and a noisy boiler. Find out more → 
Landlord gas safety (CP12) Your yearly landlord gas safety certificate, sent by Dexter, from £70. Find out more → 
General plumbing Leaks, taps, toilets, sinks and under-sink water heaters. Priced on the phone. Find out more → 
Ideal, Vaillant and Worcester Bosch, each sized to your home. Dexter fits every major brand, so ask if you would prefer Baxi, Main, Glow-worm, Viessmann or ATAG.
Ideal Logic Max Combi2 Best for: flats and homes with one bathroom C24 · C30 · C35 
Vaillant ecoTEC plus Best for: most family homes 826 · 832 · 836 
Worcester Bosch Greenstar 8000 Best for: larger homes and busy bathrooms 32 · 36 · 40 kW In every boiler price
Removal and recycling of your old boiler · Gas Safe installation by Dexter · Chemical system flush · Magnetic system filter · Programmable room thermostat · Inhibitor (system protection) · Flue kit · Carbon monoxide alarm · Manufacturer warranty registered for you · Building Control certificate
Figures from the manufacturers' current UK ranges: Ideal Logic Max Combi2, Vaillant ecoTEC plus 826 to 840 and Worcester Bosch Greenstar 8000+, the current version of the 8000 Life. Warranties need the boiler registering and servicing every year; manufacturer terms apply. Dexter confirms the exact model and size after looking at your home.
Fitted by DexterAbout DWM
DWM Plumbing, Heating & Cooling Ltd is run by Dexter Whittaker-McGreal, a heating engineer based in Andover. Dexter prices the job, carries out the work and leaves the paperwork in a DWM pack, so you deal with the same person throughout.
Most of his work is new boilers, conversions from tank systems to a combi, air conditioning and servicing, for homeowners and landlords across Hampshire and Wiltshire.
The units Dexter fits are air to air heat pumps, so one unit cools the room in summer and heats it in winter. More rooms cost less each: save £300 on two and £500 on three.
Mitsubishi Electric MSZ-HR Best for: bedrooms and home offices Heats and cools 
Daikin Perfera Best for: living rooms and open plan Heats and cools 
Daikin Emura Best for: rooms where the unit is on show Heats and cools Running costs are a guide for each room size, at today's electricity price cap.
Bedroom 2.5kW unit · 6-12m² About 2p an hour to cool About 7p an hour to heat 
Living room 3.5kW unit · 12-23m² About 3p an hour to cool About 9p an hour to heat 
Home office 2.5kW unit · 6-12m² About 2p an hour to cool About 7p an hour to heat 
Open plan 5kW unit · 23-35m² About 4p an hour to cool About 12p an hour to heat Garden room 3.5kW unit · 12-23m² About 3p an hour to cool About 9p an hour to heat Figures from Mitsubishi Electric and Daikin for the current MSZ-HR, Perfera and Emura ranges, across the sizes. Running costs are illustrative, based on typical efficiency for the unit size at the Ofgem electricity price cap. Dexter fits every major brand: Daikin, Mitsubishi Electric, Samsung, LG, Fujitsu, Toshiba and Panasonic.
Lots of the villages around Andover are off mains gas. The big online installers turn oil away. For Dexter it is everyday work.
Dexter's own photos from real jobs around Andover. No stock pictures.
New boiler Worcester 4000 combi 
Conversion Warm air to combi 
New boiler Vaillant ecoTEC, garage 
New boiler 30kW combi in a loft Cylinder Unvented cylinder 
Oil Floor standing oil boiler 
Radiators Anthracite column radiator 
Air con Air to air heat pump 5.0 on Google from 63 reviews, 44 of them mentioning Dexter by name. Read them on Google
Dexter has recently supplied and fitted a new gas boiler for us. His prices are competitive and the installation was painless and went according to plan without any issues. ...
Mike TizardNew gas boiler, February 2024
Read more on GoogleDexter replaced our old vented heating system and hot water cylinder with a new combi in our loft, including a new gas run from our garage. Dexter is extremely polite, tidy and his work is first class. ...
Dean ChappellVented system to combi, April 2025
Read more on GoogleDedicated, professional and friendly, Dexter has done many jobs for us and he never disappoints! Fitting our Air-to-Air heat pump was particularly challenging so we were very glad to have such an expert doing the job.
Steve PalmerAir to air heat pump, September 2026
After smelling gas around our boiler, I called DWM and Dexter was with us within 30 mins. He diagnosed a few issues, sourced the parts and fixed our boiler within a few hours - at a very fair price! ...
Ross VickeryBoiler repair, March 2025
Read more on GoogleDexter replaced our old gravity fed water system with a new combi boiler, including removing the old pipes, header tank and cistern. Also fitted our new shower. He did a great job. Very polite and professional. ...
Nick SmithGravity system to combi, November 2024
Read more on GoogleFitted a new unvented cylinder. Removed our very old failing vented system and re-routed pipework accordingly. Cleared out the old system and left the place very tidy each day. ...
Philip EwenUnvented cylinder, August 2024
Read more on GoogleWhere Dexter works
Dexter is based at 24 Charlton Rd, Andover, so most work is a short drive away. If your village is not listed, put your postcode in the price tool or ask anyway.
Pick the job below. New boilers and air con are priced online. For everything else, send one short form and Dexter rings you back.
Use the price tool for a new boiler or air con, send the short form for anything else, or call Dexter on 07774 319391.
He talks the job through, checks anything he needs to see and agrees a date that suits you.
Dexter carries out and tests the work, registers any warranty for you and leaves the paperwork in a DWM pack.
Questions
Not sure what boiler you have? Send Dexter a photo and he will tell you.
WhatsApp DexterIt depends on your home, so answer the 9 questions in the boiler price tool and you see an estimated price straight away, fitted and including VAT. Dexter confirms the final price before any work starts.
Yes. LPG goes through the same price tool as mains gas, at the same price. Dexter is Gas Safe registered for both.
Yes. Dexter is OFTEC registered for oil. Oil boilers are priced after a quick chat or a photo, so use the oil boiler form and he rings you back.
Yes, it is one of the jobs Dexter does most. System, gravity fed and warm air setups can all go to a combi. Pick "Convert to a combi" in the price tool and the conversion is in your price.
Every major brand. The price tool shows Ideal, Vaillant and Worcester Bosch, and Dexter also fits Baxi, Main, Glow-worm, Viessmann and ATAG. Ask about any other.
Yes. The units we fit are air to air heat pumps, so the same unit cools the room in summer and heats it in winter.
As a guide, about 2p an hour to cool a small bedroom on a 28° day and about 7p an hour to heat it on a 10° day. The air con price tool shows it for every room you choose.
No. You pick your boiler or system and an install date, and Dexter rings you to confirm it. Nothing is taken from your card on the website.
Dexter is based in Andover and works across Hampshire and Wiltshire, including Salisbury, Winchester and Romsey. Put your postcode in the price tool and he will tell you if you are outside his area.
Get your boiler or air con price now, or tell Dexter what you need and he will take it from there.
