MSZ-HR is Mitsubishi Electric's cost-controlled residential wall indoor. MSZ-AY is the quiet everyday unit most UK bedroom quotes should start from. Buy HR for guest rooms and tight budgets. Buy AY for the room you sleep in. MSZ-LN is a designer and filtration step above AY, not a bigger cooler. A quote that only says Mitsubishi wall unit is mixing these.
The M Series ladder, without the brochure fog
Mitsubishi Electric's UK walls are a stack. HR holds the bottom: cooling and heating, fewer extras, a lower equipment price. AP still appears on some quotes as an older mid. AY is the current quiet workhorse. LN is the Kirigamine-style premium with colour options and Plasma Quad. EF is a flat-panel design alternative. If your quote skips the letters, ask for the indoor code.
The AY versus LN guide covers the top of that stack. This page is the value decision people actually face: pay for AY or take HR and put the money into a better outdoor position.
- HR: value indoor, still a proper Mitsubishi split.
- AY: very low indoor sound, strong heating, the default bedroom spec.
- LN: colour, Plasma Quad, occupancy sensing. Not extra kW.
- Outdoor siting still decides what the neighbour hears.
Bedrooms versus spare rooms
If the brief is sleep through a hot night, AY is usually the rational pick. HR will cool the room if the kW is right. It will not match AY's lowest fan setting, and that is the number people notice at 2am. For a box room used twice a summer, HR is honest engineering.
Heating in a UK winter is where AY's tables often look stronger at low outdoor temperatures. If the unit has to take a loft or an extension without a radiator, say so at survey. The can-air-conditioning-heat guide sits next to this page.
Cost shape
As a 2026 illustration, both live in the first-tier single-split installed band, with AY carrying an equipment premium over HR for the same capacity. Labour is almost identical. A cheap HR with a 20 m pipe run can exceed a dearer AY with a 4 m run.
Warranty follows who registered it. A five-year sticker from a company that will not answer in January is not a strategy.
Comparing quotes
Same kW, same outdoor wall, same drain. Then choose HR or AY as a feature and sound decision. If one quote is AY and the other is HR, you are not looking at a discount. You are looking at different products.
Use the quote form and name the room. Installers who stock Mitsubishi weekly will say if HR is enough for a spare room, or if AY should go on the sleeping wall.
Frequently asked questions
Is Mitsubishi HR too cheap to be any good?
No. It is a simpler indoor on the same kind of split system. It is the wrong buy only if you needed AY's night sound or heating performance and took HR to win on price.
Should I skip AY and go straight to LN?
Only if you want colour, Plasma Quad or occupancy sensing and the indoor is on display. LN is not meaningfully more cooling. Read the AY versus LN guide.
Can HR and AY share one outdoor?
On a compatible Mitsubishi multi-split outdoor, often yes. Confirm the indoor codes against that outdoor's list and the simultaneous capacity.
Core buying guides
Start with these high-intent guides, then dig into the rest of the library.
Related guides
Sources and further reading
How this guide was prepared
This guide was written by the Local AC Installers Editorial Team. We compare official guidance, legislation and established consumer information, separate general information from project-specific advice, and show publication dates and sources. We do not accept installer accreditation claims at face value.