How HMO Room Size Rules Can Affect Investment Performance

April 7, 2026

When investors assess an HMO opportunity, they often focus on yield, purchase price, headline rental income, and the number of rooms. Those metrics matter. However, room size rules can have a much bigger impact on long term investment performance than many buyers first realise.

In our view, room size is not a minor compliance detail. It sits right at the centre of tenant demand, tenant retention, regulatory resilience, and future income protection. For over 34 years of developing and managing HMO properties, we have always done the right thing by ensuring that the rooms in the HMOs we develop and sell to our investors exceed the minimum HMO room standards by a considerable amount. That approach is not accidental. It reflects experience, caution, and an understanding of what helps an HMO perform well over time.

Why room size matters in HMO investment

Minimum room size rules exist for a reason. People need enough space to live properly, store belongings, work, relax, and feel comfortable in their home. An HMO room might look acceptable on paper when it just reaches the legal minimum, but that does not mean it creates a good living environment or a strong investment.

A room that only just passes minimum standards often feels exactly that, minimal. It may be technically lettable, but it can still be less desirable to tenants. In practice, smaller rooms can lead to more objections during viewings, slower lets, more frequent move-outs, and increased pressure on rents. Those issues all affect performance.

This is where many cheaper HMO developments go wrong. Too many developers sell cheap HMO properties because they are using cheap, tiny houses and cramming them with lots of minimum sized rooms. Then they wonder why tenant turnover is ridiculously high. The answer is usually quite simple. Tenants do not want to stay in cramped accommodation any longer than they have to.

Cheap room design often creates expensive problems

A lot of investors are drawn towards low entry prices. That is understandable. Yet in HMOs, a cheaper purchase price can sometimes hide a poor layout, poor room design, and a weak long term proposition.

Any developer building rooms to a minimum room size and no larger is massively doing you a disservice. They may be maximising room count on day one, but they are not necessarily building a property that will attract and keep good tenants over the years ahead. That difference matters.

High turnover is not just an inconvenience. It affects void periods, remarketing costs, cleaning costs, maintenance scheduling, admin time, and the overall stability of cash flow. A property filled with small, cramped rooms may still produce rent, but it often produces more friction as well. Over time, that friction reduces the quality of the investment.

By contrast, a well designed HMO with generously sized rooms gives tenants a better standard of living. That tends to support longer stays, steadier occupancy, and a more robust income profile.

Better rooms usually mean better tenant retention

Tenant retention plays a major part in HMO performance. A tenant who stays longer reduces the cost and disruption of constant changeovers. They are also more likely to look after the property well and settle into the house.

Room size has a direct effect here. When tenants feel they have genuine personal space, they are more likely to view the property as a home rather than a short term stopgap. That can be especially important in professional HMOs, where many tenants are balancing work, privacy, and quality of life.

Most of our rooms are 10 square metres plus an ensuite, and all of our properties have an ensuite. That standard gives tenants far more usable space than the bare minimum and provides an overall living experience that is much stronger than what is often found in cheaply developed stock. A larger room with its own ensuite simply offers a more comfortable and practical setup than a squeezed room in an over-packed house.

That matters for performance because happier tenants tend to stay longer. Longer stays often support more consistent returns.

Room size can protect income if regulations tighten

This is one of the most overlooked parts of HMO investing. Many buyers assume that if a room is legal today, it will always be legal. That is not a safe assumption.

Standards can change. Local authorities can become more demanding. Licensing expectations can tighten. What passes today may not be enough tomorrow. Investors who buy HMOs with rooms designed only to scrape over the line can leave themselves exposed to future rule changes.

That is one reason we have always believed in exceeding standards by a considerable amount. If authorities were ever to increase minimum room requirements, our investors are not left with a property containing rooms that can no longer legally be let due to their size. That is a major layer of protection.

Far too many investors unfortunately end up in the opposite scenario because they go with inexperienced, cheaper developers. The property may look attractive at first because it offers more rooms and a lower entry price. Yet if room sizes are too tight, the investor carries much more regulatory risk. In the worst cases, a room may become unusable, which can damage rental income and reduce the overall value of the asset.

More rooms does not always mean a better investment

A common mistake in HMO investing is to judge value by room count alone. More rooms can look better in a spreadsheet. However, a six bedroom HMO made up of cramped, borderline rooms is not automatically better than a five bedroom HMO with spacious ensuite rooms that tenants genuinely want to live in.

Headline figures can be misleading. Investment performance depends on how sustainable the income is, how strong tenant demand remains, how often tenants leave, and how exposed the property is to compliance issues. Bigger, better rooms can support all of those areas more effectively than an over-optimised layout.

This is where experience really counts. For over 34 years, we have seen what works in the real world, not just on paper. We know that building above minimum standards is not overkill. It is sensible risk management and good asset design.

Why experienced HMO developers take room size seriously

Inexperienced developers often focus on what they can get away with. Experienced developers focus on what will continue working for the investor long term.

That difference shapes everything. A developer with real HMO experience understands that room sizes affect more than licensing compliance. They affect tenant satisfaction, property reputation, occupancy stability, resale quality, and resilience against regulatory change.

We have always taken the longer view. That is why we make sure our HMOs offer generously sized ensuite rooms and a standard of accommodation that goes well beyond the minimum. It is better for tenants, and it is better for investors.

When an investor buys a poorly designed HMO with undersized rooms, they often inherit the future problems that were designed into the property from day one. When an investor buys a well planned HMO with larger rooms and stronger fundamentals, they are in a much better position to enjoy reliable performance.

Room size rules should shape how you judge value

A cheap HMO is not always a good HMO. A high room count is not always a strong room count. A room that is legal is not always a room that performs well.

Investors should look beyond the headline deal and ask better questions. How large are the rooms in practice. Do they only just meet minimum standards. Would tenants genuinely want to stay there. Could the property still perform well if standards tightened in future. These questions can tell you far more about long term quality than a sales brochure ever will.

At Foot Forward, we have spent over 34 years developing and managing HMO properties with that long term mindset. We do not believe in cutting room sizes down to the absolute minimum just to cram in extra doors. We believe in building HMOs that work properly, protect our investors, and provide a better standard of living for tenants.

If you are looking for HMO investments built with long term performance in mind, you can view our available opportunities here: HMO properties for sale.