Office air conditioning rarely fails outright. It just never quite suits anybody, and two summers later half the floor has brought in desk fans while the other half sits in coats. That outcome is decided long before anyone drills a hole. Here is what actually matters when you are specifying a system for an office.
In this guide
An office is not a big house
It is tempting to treat a commercial job as a domestic one with more units on the wall. That assumption is behind most of the office systems we get called out to fix.
A house is predictable. The same few people, doors that get closed, a settled idea of what comfortable means. An office is none of that. It fills up in the morning, empties at lunch, fills again, hosts a meeting that puts a dozen people in one glass box, and the sun tracks across the whole thing all day. You are not cooling a space, you are cooling a space that keeps changing, and nobody is going to stand at a controller managing it.
Occupancy is the load
In an office, the biggest heat sources are frequently the people and the equipment, not the weather. Every person gives off heat constantly, and so does every laptop, monitor, printer and bank of lights. Put thirty people and their kit on a floor and you have a permanent heat gain whether it is July or January. That is why offices need cooling in months when nobody at home would dream of it.
So a system sized from a floor area and a compass bearing will be wrong. We ask different questions at survey. How many desks, and how many are occupied on a normal day? Where do people gather, and when? Has hybrid working left you with more room than you need? A floor designed for eighty people that now holds thirty-five behaves completely differently, and a system specified for the old occupancy spends its life oversized, short cycling and costing more than it should.
Zoning, and the argument it prevents
If you take one thing from this article, take this. The single most common cause of complaints in an open plan office is one thermostat trying to serve a sunny side and a shaded side.
The south and west facing side gets sun through the afternoon. The north side does not. Those two halves want different things at three o’clock and a single control cannot give both, so it satisfies the sensor it happens to be near and the far end suffers. Zoning fixes it, and it has to be decided at design stage, because retrofitting it into an installed system is expensive in a way that doing it properly first time is not.
- Split by orientation first. The sunny side and the shaded side are almost always different zones. This is the big one.
- Separate the meeting rooms. They go from empty to full in minutes. Tie them to the open plan floor and everyone loses.
- Separate anything with its own heat source. A print room or a comms cupboard is not a bank of desks.
- Think about who is in early and who is in late. Zoning means you are not conditioning an empty floor for one team.
Choosing the indoor units
Unit type matters more in an office than at home, because you are distributing air across a wide space rather than into a bedroom.
- Ceiling cassettes. Sit in a suspended ceiling and push air in four directions. For open plan they are usually the right answer, because even distribution is the whole job. They need a ceiling void.
- Ducted units. Hidden entirely, with air delivered through grilles. The tidiest option and the most flexible for an awkward layout, but more work to install.
- Wall mounted units. Cheapest and quickest, and fine for a private office. On a large open floor they blow from one end, which is the uneven result you are trying to avoid.
- Floor standing or under ceiling units. Useful where there is no void and no sensible wall, which comes up often in older buildings around central Middlesbrough and Stockton on Tees.
A newer unit on a business park in Thornaby or Ingleby Barwick usually has the void and straightforward routes. A converted building in Middlesbrough might have solid walls and a conservation constraint on the elevation. Both are doable, but they are not the same job, and anyone pricing them the same has not looked properly.
Where the outdoor unit goes
This is the question that quietly derails commercial projects, usually late, after everything else has been agreed. The outdoor unit needs air moving freely around it, a sensible pipe route back inside, and somewhere the noise will not upset a neighbour. On a shared business park you also need somewhere the landlord will agree to. What does not work is a spot chosen because it was the only place left.
Raise noise early rather than late. Modern equipment is far quieter than its reputation, but a unit sited badly against a hard wall in a small enclosed yard sounds worse than the same unit sited sensibly. If you have residential neighbours, which plenty of Teesside town centre offices do, that is a survey conversation, not an after the complaint one.
What the lease says
Check it before you get attached to a design. Leases commonly have something to say about alterations, the external appearance of the building, and what happens at the end of the term. Some require the system to be removed and the building reinstated, which is a cost worth knowing at the start rather than the end.
The lease also bears on who is responsible for the system once it is in. As a business you are the operator of equipment containing fluorinated refrigerant, and that carries real duties which start the day it is commissioned. Responsibility usually follows control, so if you control the system they are generally yours. Our F-Gas compliance checklist for Teesside businesses sets out what they are and how to find out where you stand.
Installing around your working day
Every business asks the same thing, and it is the right thing to ask. How much of this lands on us? It depends on planning rather than speed. Commercial work gets planned around trading hours. We frequently work evenings and weekends so the floor is usable every working day, and we stage the job so no more than one area is affected at a time.
Agree that schedule before you sign anything. Out of hours working is not a favour bolted on at the end, it is part of the plan and part of the price, and a quote that has not accounted for it is not a quote for your job. Agree access too: who holds keys, who gets called at nine on a Saturday, what happens with the alarm.
Controls, and who is allowed to touch them
A system nobody understands ends up on one setting all year. That is uncomfortable, expensive and entirely avoidable.
Decide early who controls what. Complete freedom on every controller sounds fair and produces chaos, because thirty people have thirty opinions and the setpoint moves all day. Locking everything down centrally means people who are genuinely too warm have no way to say so except by complaining to you. The middle ground works best: sensible central limits, local adjustment inside a range, and timers so the system is not conditioning an empty building overnight.
Then insist on a proper handover. Not a manual left on a desk. Someone walking your office manager through what the modes do and why setting sixteen degrees does not cool the room any faster. Ten minutes at handover saves a year of the system being misused.
The cheapest office system to buy is frequently the most expensive one to own. Sizing, zoning and maintenance decide that, not the badge on the unit.
Talking it through across Teesside
We are a family run business on North Ormsby Road in Middlesbrough, covering roughly twenty miles around it: Stockton on Tees, Thornaby, Billingham, Norton, Yarm, Eaglescliffe, Ingleby Barwick, Redcar, Marske, Saltburn, Guisborough, Marton, Hartlepool, Peterlee and Darlington. We look after single sites and multi-site portfolios, and we service any make, model or age of equipment, including systems we did not install.
A site survey is free and there is no obligation. We will look at your floor, ask how it is actually used through the day, and give you a clear itemised specification you can take to whoever signs it off. If we think you need less than you were expecting, we will tell you that too. Give us a ring on 01642 680 873.
