What we do
Domestic and commercial work across South East London — with the airflow measured at the grille, not assumed from the box.
Domestic and commercial ventilation, heating and cooling — designed properly, installed neatly, and commissioned so the airflow is measured rather than assumed.
Whole-house mechanical ventilation with heat recovery — designed, ducted and balanced so every room gets its share without throwing your heating out of the window.
Rigid and spiral ductwork, sized and routed to keep resistance and noise down. Set out square and bracketed properly — because on an exposed run the setting-out is the finish.
Air handling units and fan coil units set, connected and commissioned — plinths, anti-vibration mounts, flexible connections and access left where the next person can actually reach it.
Bathroom, kitchen and utility extract that meets the Part F rate at the grille, not just on the box. Ducted to outside properly, never into a loft void.
Installation and planned maintenance for split and multi-split systems — filters, coils, condensate and performance checked before the hot weather finds the fault for you.
A system nobody services stops doing what it was installed to do, quietly. Pick the interval that suits the kit and we book it in rather than waiting for you to notice.
Measurement first: humidity, surface temperatures and actual extract rates. You get a written report on what is causing it, not a guess and a quote for a bigger fan.
Supply and extract for units, venues and workspaces — coordinated with the other trades so the ductwork lands where the ceiling design says it should.
Investigation, a written report naming the cause, the fix, and a dated evidence trail — because the question is no longer whether you fixed it, but whether you can show what you did and when.
Heat recovery
An MVHR unit extracts damp air from your wet rooms and supplies filtered fresh air to the bedrooms and living space, passing the two streams either side of a heat exchanger so most of the warmth stays in the house.
It only works if the ducting is right. Insulated where it runs cold, kept as short and straight as the building allows, and balanced room by room at commissioning — otherwise you have an expensive box moving the wrong amount of air.
See how it works in your homeHeat recovery, in section
An extract fan throws your heating out through the wall. A heat recovery unit takes the warmth out of the stale air on its way past and hands it to the fresh air coming in. Scroll to follow one lungful of air all the way through the machine.
Illustrative figures at 85% heat recovery on a 3 °C day. The real numbers depend on the unit and the duct layout, and are proved by measurement at commissioning — not by the brochure.
Extract · 21 °C
A valve in the bathroom ceiling pulls air out continuously — from the rooms where the moisture is actually made. It leaves at room temperature, taking the moisture with it before it reaches a cold wall and turns into condensation.
Exhaust · 6 °C
Through a filter, through one half of the exchanger, through the fan and out to the wall grille. By the time it reaches the outside it is close to outdoor temperature — the warmth you paid for has been left behind in the unit.
Intake · 3 °C
Filtered outdoor air enters through its own grille, set well away from the exhaust so the unit can't breathe back in what it has just thrown out, and runs into the other half of the exchanger. The plates keep the two streams apart: heat passes between them, air never does.
Supply · 18 °C
The warmed fresh air is delivered to the bedrooms and living room. That is the whole trick: the full air change the regulations ask for, without paying to heat the house twice — which is exactly what an extract fan on its own makes you do.
A black bathroom ceiling is not really a decorating problem. It is a disrepair claim, a renegotiated sale, a void month, or a tenant who has stopped answering the phone — and by the time it is any of those, the question is no longer whether you fixed it. It is whether you can show when you were told, what you found, what you did and when you did it.
That is a record-keeping problem as much as a ventilation problem. Most contractors hand you a paper invoice and nothing else. We do both halves, and the record builds itself.
The Homes (Fitness for Human Habitation) Act lets a tenant take you to court directly, and damp and mould is a category 1 hazard. Repainting it is not a defence — the cause has to be dealt with, and you need to be able to prove it was.
You get a report naming the cause and a commissioning certificate proving the fix works.
You are the one taking the call, and you are carrying it with the landlord and the tenant at the same time. What you need is one contractor who goes out, reports back in writing, and gives you something you can forward the same afternoon.
You get a dated record per property, in an account you can pull it out of at any time.
Communal extract that has not been touched since it was fitted, flats with no working ventilation, and a Section 20 to get through before anything can happen. A specified job with a measured outcome is a great deal easier to consult leaseholders on than “we will put some fans in”.
You get a survey of the whole block, a specification you can consult on, and figures at the end that show what was actually delivered.
A survey that flags condensation or mould takes the momentum out of a sale and puts a number in the buyer’s head. Nine times in ten it is a ventilation shortfall, not rising damp — and that is a fixable, provable, quotable thing.
You get a fast survey, a written cause and a fix that closes the point out before exchange.
Surveyors and damp specialists: if you diagnose but do not install, send it over. We do not survey for damp causes in competition with you — we take the ventilation half, do it properly, and hand your client back a measured figure with your name still on the diagnosis.
Not a look and an opinion. A damp and mould survey with the readings written down as they are taken: relative humidity, surface temperatures at the cold spots, moisture readings, and the airflow the existing extract is actually achieving.
Why it mattersA measured airflow is the difference between “there is a fan in there” and knowing whether it moves the air the room needs. Most of the ones we test do not.
A written report naming the cause, not the symptom — a ventilation shortfall against the Approved Document F minimum, a cold bridge, a defect, or an occupancy load the fabric cannot carry.
Why it matters“Tenant lifestyle” is the answer that ends up in front of a judge. A figure against a standard is the answer that ends the argument.
Extract upgrades, continuous mechanical extract, positive input, or full heat recovery where the property warrants it — then commissioning with a calibrated anemometer and a certificate of the rate measured at each valve.
Why it mattersA system that meets the figure on paper regularly fails on site. The certificate is what stops the same property coming back next winter as a claim.
Worth saying plainly, because plenty of people will imply otherwise. Awaab’s Law is named after Awaab Ishak, who died in 2020 after prolonged exposure to mould in his family’s flat. It came in through the Social Housing (Regulation) Act 2023, and the first phase of it took effect for social landlords on 27 October 2025 — fixed legal timescales to investigate a reported damp or mould hazard, report the findings in writing and start the work.
For privately rented homes it is not in force. The Renters’ Rights Act 2025 gives the government the power to extend it, and the published roadmap puts that in a later phase, subject to consultation. No commencement date has been set. Anyone telling you there is one is guessing.
It is worth knowing now, because the record it will ask you for is the record you should be keeping anyway — and the properties that will struggle are the ones with no before-and-after figures on file. Everything above already produces that record. Nothing needs to change when the timescales land.
Not legal advice. Awaab’s Law currently applies to social housing; the extension to privately rented homes under the Renters’ Rights Act follows its own timetable, and the regulations are amended from time to time. Check the current position, or take advice, for what applies to your properties today. What we can tell you precisely is what a property needs under Approved Document F, and prove by measurement that it is achieving it.
We built our own engineer’s app, and every client gets the portal side of it. It is not a brochure — it is where the job actually lives, and the readings land in it as the engineer records them on site.
The reason that matters when you manage property is simple: the record you would have to produce is the same record we have to keep anyway to do the job properly. So you get it as a by-product, dated, rather than reconstructing it from an invoice eighteen months later when somebody asks.
See the client portalOne property or two hundred — tell us what you have and where, and we will tell you what it needs.
Talk to us about a portfolioVentilation is the only thing in a house that quietly stops working without ever breaking. Nothing trips, nothing leaks, nothing makes a noise — the filters load up, the airflow halves, and the first anyone knows is a black line round the bathroom ceiling two winters later.
So we do not sell a callout. We sell a visit that ends in a measured figure, the same way the installation did.
Filters to the manufacturer’s interval, heat exchanger drawn and cleaned, condensate trap checked, and the unit re-balanced — then every valve re-measured and the figures written down.
A loaded filter set can take a third off the airflow before anyone notices. Re-measuring is the only way to know it is still doing what it was commissioned to do.
Performance tested at the grille with a calibrated anemometer against the Approved Document F rate for that room, cleaned, and re-commissioned. If it cannot make the figure, you get told why.
Most of the fans we test in older properties do not hit their rate. A test is what turns “there is a fan in there” into something you can act on.
Filter changed, airflow checked at the diffuser, heater and controls tested, and the loft conditions round the unit looked at while we are up there.
A PIV pushing through a blocked filter is a fan heating a loft. They are cheap to service and almost never are.
Filters, coils, condensate and drainage, electrical connections and a performance check before the hot weather finds the fault for you.
Refrigerant circuit work — recovery, charging and leak testing — is carried out under F-Gas certification by our refrigerant partner, because it is illegal to do otherwise. The work listed above needs no F-Gas certificate and we do it ourselves.
One visit per property per year, planned round the summer rather than squeezed into the winter when everything else is going wrong. Each one ends with a dated certificate carrying the measured figures, filed against that property in your account.
That is the record that answers a complaint before it becomes a claim: not “it was serviced”, but what it was achieving, on what date, against what standard.
Ask about a service planYou do not need the ventilation lecture. You need the ductwork in between the joists before the boards go on, on the day you said, and the numbers for building control at the end of it.
First fix
Ventilation is won or lost before the ceiling goes on. Once plasterboard is up, the duct route is fixed, and a run forced around a joist it was never planned for will cost you airflow for the life of the building.
We set out first fix against the drawings and the other trades — joist positions, service voids, where the soil pipes and cabling are already going — so the ducting takes the shortest sensible route rather than the last gap left over.
Talk to us before first fix
Send us a message with what you have noticed at home. We will tell you honestly whether you need a survey, a system, or neither.
Trained on the systems we install
Most trade sites show you a row of logos. These are the actual certificates, both sat in August 2026. Tap either one to read it, or download the PDF.
