HVAC Guide

HVAC stands for Heating, Ventilation and Air Conditioning. In homes it usually means equipment that heats or cools your space and moves air for comfort. Split air conditioners, heat pumps and mechanical ventilation all sit under the HVAC umbrella.

A split system moves heat rather than making cold air from nothing. Refrigerant absorbs heat from your room at the indoor unit (evaporator), travels to the outdoor unit (condenser) and releases that heat outside. The fan blows the now-cooler air back into the room. It is the same principle used in fridges — just sized for a whole room or home.

Because the system is dumping the heat it removed from your room. If the outdoor unit is blocked, dirty or too close to a wall, it cannot reject heat efficiently and cooling performance drops. Keep clear space around it and keep the coil clean.

Cooling mode moves heat from inside to outside. Heat pump mode reverses the cycle so the outdoor unit absorbs heat from outside air (even in cool weather) and releases it indoors. Modern inverter splits are often used for both summer cooling and winter heating.

Refrigerant is the fluid that carries heat around the system. It stays sealed inside pipework and units. You should not breathe leak fumes or attempt DIY top-ups — F-Gas law in the UK restricts who can handle refrigerant. If you suspect a leak (hissing, oily marks, poor performance), switch off and call a REFCOM registered engineer.

Yes. When warm room air passes over the cold indoor coil, moisture condenses and drains away. That is why you may see a drain pipe from the indoor unit. Lower humidity often makes a room feel cooler at the same temperature.

Capacity is measured in kilowatts (kW) — how much heating or cooling the system can deliver. Too small and it will run constantly; too large and it may short-cycle and feel clammy. Room size, insulation, sun-facing windows, ceiling height and how many rooms you want to treat all matter. A proper survey is the only reliable way to size a system — online guesses are a starting point only.

A single split is one outdoor unit paired with one indoor unit — ideal for one main room. A multi-split uses one outdoor unit feeding several indoor heads in different rooms. Multi-splits save outdoor space but need careful design so all rooms are served fairly.

Inverter systems vary compressor speed to match demand, which usually means smoother comfort, quieter running and lower electricity use at part load. Most quality domestic installs today are inverter-based. Non-inverter (fixed speed) units are simpler but less efficient for typical home use.

Sometimes, with a well-designed multi-split or a whole-home heat pump system — but not every floor plan suits one box. Long pipe runs, room usage patterns and building fabric all affect what is sensible. Survey and design come first.

Wall-mounted (high-wall) units are common, cost-effective and easy to maintain — you see the unit in the room. Ducted systems hide grilles in the ceiling and suit new builds or refurbishments with void space. Ducted costs more and needs space for ductwork; wall splits are often the practical choice in existing UK homes.

Look for a reputable manufacturer, a clear warranty, UK parts availability and an installer who designs and commissions properly — not just the cheapest box. Artifis selects equipment for reliability, efficiency and aftercare; your survey compares sensible options for your home.

A straightforward single-room split often completes in one day once materials are on site. Multi-room systems, long pipe runs, scaffold or complex electrics can take two or more days. Your quote should state the expected programme after survey.

Many domestic wall-mounted outdoor units fall under permitted development if placement and size rules are met — but listed buildings, conservation areas and flats may need consent. Leasehold properties often need landlord approval too. We check constraints during survey.

Prefer a stable, well-ventilated position with clearance for airflow and future service access — usually on an external wall near the indoor room. Avoid boxing it in, placing it above bedrooms if noise is a concern, or crowding it with bins and plants.

Outdoor units need a dedicated circuit from your consumer unit — typically via SWA cable and an outdoor isolator. Distance, route and board capacity are surveyed first. Some homes need a minor works upgrade; others need a sub-board. Artifis can carry out the electrical package where quoted.

Flats often need freeholder or management company approval for external equipment and penetrations. Renters need landlord consent. Indoor units still need pipe routes and drainage — survey confirms what is feasible.

Homeowners must not break into refrigerant circuits without F-Gas certification. Poor DIY work risks leaks, poor performance, water damage and invalid warranties. Commissioning, pressure testing and electrical certification should be done by qualified trades.

Modern heat-pump splits and dedicated air source heat pumps can heat efficiently in typical UK winter temperatures. Performance drops in extreme cold, so design and emitter sizing (radiators or fan coils) matter. Many homes use heat pumps as the main heat source; others combine with existing boilers during transition.

Air source units take heat from outdoor air — lower install cost, less garden disruption. Ground source uses buried or borehole collectors — higher install cost, often steadier efficiency. Both can qualify for MCS certification and grants when installed to standard.

The UK Boiler Upgrade Scheme (BUS) offers a grant towards replacing fossil-fuel heating with an MCS-certified heat pump in eligible homes — currently up to £7,500 for most properties (higher caps may apply for oil/LPG in some cases; check official guidance). Installers apply on your behalf after MCS-compliant installation.

Often yes, but fabric matters. Draught-proofing, insulation and correctly sized emitters improve comfort and efficiency. A heat-loss survey identifies whether radiators need upsizing or whether hybrid approaches make sense.

Quality units operate well below 0 °C, though output and efficiency reduce as it gets colder. Inverter compressors and defrost cycles manage ice on the outdoor coil. Design should consider your coldest typical week, not just average weather.

MCS is the UK quality mark for small-scale renewable heat (and related standards). MCS-certified design and install is required for BUS grant eligibility and gives documented commissioning — important for warranties and future property sales.

Running cost depends on kW output, hours of use, set temperature, insulation and unit efficiency. As a rough guide, a modern ~2.5 kW inverter split cooling one room might use on the order of a few kilowatt-hours over several hours — check your tariff. Heat pump heating can be competitive vs direct electric heat when designed well.

COP (Coefficient of Performance) is instant efficiency — heat delivered divided by electrical power at a given moment. SCOP (Seasonal COP) averages performance across a heating or cooling season. Higher numbers mean more heat or cool per unit of electricity over time.

Many people find 21–24 °C comfortable for cooling. Each degree lower increases electricity use. For heating, 18–21 °C is typical. Avoid huge swings — steady settings with inverter control usually cost less than repeatedly maxing out then switching off.

Keep filters clean, close doors/windows while running, use timer or schedule modes, shade sunny rooms, maintain outdoor clearance and service the system annually. Good insulation and draught sealing reduce the load on any HVAC system.

For heat-pump and inverter systems, long off periods in extreme weather can mean more catch-up work later. Many homes use a modest setpoint with scheduling — cooler when out, comfortable when home — rather than full off/on cycling every hour.

Domestic splits benefit from an annual check — filters, drains, coil condition, refrigerant integrity and electrical connections. Landlords and commercial sites often have stricter schedules. Regular service keeps efficiency up and catches small faults early.

Common causes: dirty filters, blocked outdoor coil, wrong mode (heat instead of cool), set temperature too high, closed vents, refrigerant issue or failed component. Check filters and mode first; if performance is still poor, book an F-Gas qualified engineer — do not guess at gas charges.

Condensate should drain away through a pipe. Blocked filters, a kinked drain hose or a blocked trap can cause overflow and dripping. Algae growth in stagnant drain lines is common — regular cleaning helps.

Biofilm on the indoor coil or drain pan often causes musty smells — especially after long idle periods. Professional coil cleaning and drain treatment help. Persistent burning smells mean switch off and call an engineer immediately.

Yes — most wall units have washable mesh filters accessible by opening the front panel. Vacuum or rinse gently, dry fully, then refit. Monthly checks in heavy use seasons are worthwhile. Deep coil cleaning is a professional job.

Light frost in heat mode can be normal during defrost cycles. Heavy ice in cooling mode or continuous icing in mild weather suggests airflow blockage, low refrigerant or a fault — turn off and get it checked.

Could be a failing compressor, damaged cable, moisture ingress, loose connection or an undersized circuit. Do not keep resetting blindly — an electrician or HVAC engineer should test the circuit and unit safely.

Confirm power and isolator are on, remote batteries and mode (cool/heat/fan), set temperature, clean filters, clear outdoor obstructions and check the drain is not blocked. If error codes persist or there is noise, smell or leak — call an engineer.

Properly maintained AC improves comfort and can reduce heat-related illness. Problems come from neglected filters (dust and mould spread) or very dry air if run aggressively. Clean filters, good ventilation and sensible setpoints keep indoor air healthy.

Cooling removes some moisture — which helps in humid summers but can feel dry if run continuously at very low temperatures. Moderate setpoints and breaks in use usually avoid noticeable dryness.

Quality inverter units are often quiet indoors — roughly conversation level on low fan speeds. Outdoor units are louder; placement away from bedroom windows and soft mountings help. Manufacturer sound data (dB(A)) is compared during design.

Consider distance to boundaries, night-time run schedules and mounting vibration. Planning and lease rules may apply. Survey should flag sensitive locations and quieter equipment options where needed.

Standard mesh filters catch dust and large particles. Finer filtration or dedicated purifiers can help pollen-sensitive users but need matching airflow and maintenance. HVAC filters are not a substitute for medical advice.

REFCOM is a UK F-Gas company certification scheme. Businesses that install, service or dispose of refrigerant equipment must be certified and use qualified engineers. Artifis is a REFCOM F-Gas certified company — verify on the public REFCOM register.

Only F-Gas certified engineers employed by (or contracted to) a certified company may break into the refrigerant circuit, leak-test and recharge. Gas Safe covers gas boilers — not split AC refrigerant work.

New circuits near consumer units usually need compliance with Part P / Building Regulations via a registered electrician or local authority sign-off. Artifis electrical packages are specified to meet UK wiring rules.

Always. A proper quote covers scope, equipment class, warranty, payment stages and what is excluded (e.g. making good, scaffold, unusual electrical upgrades). Artifis works from survey to formal quotation — not open-ended verbal guesses.

Yes — Artifis is a REFCOM F-Gas certified company for domestic and light-commercial air conditioning from our Leicester base, with priority coverage in Loughborough, Coalville, Lutterworth, Hinckley, Melton Mowbray and Market Harborough.

Use the online survey at artifis.co.uk/survey or call 0116 403 4444. You speak directly to the engineer — not a call centre. We aim to respond within one business day.

Artifis installs air source and ground source heat pumps to MCS standard with eligible BUS grant support where applicable. Survey confirms property suitability and paperwork.

Yes — where quoted, Artifis provides the outdoor supply package (isolator, SWA and connection) to UK electrical standards. Scope and allowance are confirmed at survey.