The HMO Landlord’s Guide to Slashing Heating Costs:

Engineer’s Advice on Boiler Efficiency and Control

Let’s be direct. If you’re an HMO landlord in London, your single biggest, most unpredictable running cost isn’t council tax, it isn’t maintenance, it’s your heating bill. It’s the one cost that you feel you have absolutely no control over. You have multiple tenants, each with their own schedule, their own idea of what’s “warm,” and their own tendency to turn the thermostat up and forget about it.

In my years as a heating engineer, I’ve seen the astronomical gas bills that land on the doormats of HMO properties. I’ve spoken to landlords who are tearing their hair out because their profits are being quite literally burned away. They feel powerless. But what if I told you that you have more control than you think?

Managing the heating in a House in Multiple Occupation isn’t about telling your tenants to put on another jumper. It’s about smart strategy, combining the right hardware with intelligent control. This is the professional’s guide to taking back control of your biggest expense and making your HMO property a more profitable, efficient, and attractive investment.

Understanding the HMO Profit Drain

Before we get to the solutions, let’s diagnose the problem. The running costs of an HMO go far beyond the mortgage. You have void periods, general maintenance, letting agent fees, and the ever-present costs of compliance. But while most of these are relatively fixed, your energy bill is a wild card.

The reason heating costs spiral out of control in an HMO is simple: a standard heating system is designed for a family, not for a group of individuals. A family has a shared routine. They wake up at the same time, leave the house together, and go to bed at similar times. An HMO is the complete opposite.

The student in Room 1 is up at 7 am. The hospitality worker in Room 2 doesn’t get home until after midnight. The remote worker in Room 3 is home all day. In this scenario, when does the heating ever get turned off? The answer is never. The system runs constantly to cater to the one person who happens to be in and feeling chilly, costing you a fortune to heat empty rooms. This is the core problem we need to solve.

The Foundation: Why Your Boiler is Everything

You can have the fanciest controls in the world, but if the “engine” of your heating system is old and inefficient, you’re fighting a losing battle. The boiler is your first and most important line of defence against high bills.

• The Efficiency Gap: If your HMO is running on a boiler that is 10-15 years old, it’s likely a ‘G-rated’ model, operating at less than 70% efficiency. For every £100 you spend on gas, £30 is being completely wasted as heat pouring out of the flue. A modern, A-rated condensing boiler operates at over 90% efficiency. That’s a 20% saving right off the bat. In an HMO with its high-demand heating, this doesn’t just save you a couple of hundred pounds a year; it can save you well over £1,000 annually. The payback period for a new boiler in an HMO is significantly faster than in a standard family home.
• Correct Sizing: It’s not just about efficiency; it’s about power. An undersized boiler will constantly struggle to meet the demands of multiple tenants wanting hot water, leading to complaints and poor performance. An oversized boiler will “short cycle”—firing up and shutting down constantly, which is incredibly wasteful and causes premature wear on components. A professional engineer will calculate the exact size (kW output) required for your specific property, ensuring it runs at its most efficient point.

Upgrading to a modern, correctly-sized boiler is the single biggest investment you can make to reduce your running costs. It’s the foundation upon which all other savings are built.

The Game-Changer: Taking Control of the Heat

Once you have an efficient boiler, the next step is to manage how and when it’s used. This is where modern technology becomes an HMO landlord’s best friend.

• The Standard Smart Thermostat (Good): A smart thermostat like a Nest or Hive is a great starting point. It allows you to set detailed heating schedules from your phone. This is a big improvement over a basic programmer, but it still treats the entire house as one single zone. It doesn’t solve the problem of heating empty rooms.
• The Ultimate Solution: Smart Thermostatic Radiator Valves (TRVs) This is the technology that truly revolutionises HMO heating management. Smart TRVs are individual thermostats that you fit to each radiator. They all connect wirelessly to a central hub and an app on your phone. This is what it allows you to do:
  1. Zone Control for Every Room: You can set a different temperature and schedule for every single bedroom and common area.
  2. Set Limits: You can give tenants control to adjust their own radiator, but only within a range you define (e.g., they can turn it up to a maximum of 21°C). This stops the tenant who likes to live in a sauna from costing you a fortune.
  3. “Empty Room” Detection: When a tenancy ends, you can set that specific room to a low-cost “frost protection” mode (e.g., 12°C) from your phone, without affecting the heating for the rest of the house.
  4. Optimisation: The system can automatically turn off radiators when it detects an open window, saving even more energy.

Smart TRVs are the answer. They give tenants a sense of personal control while giving you, the landlord, ultimate control over the maximum temperature and overall running costs. It is the perfect balance for an HMO property.

Don’t Forget Your Legal Duties: Maintenance is Key

An efficient system is only efficient if it’s well-maintained. As a landlord, this isn’t just a good idea; it’s a legal requirement.

• The Annual Gas Safety Certificate (CP12): This is your non-negotiable legal duty. Every 12 months, a Gas Safe registered engineer must check all gas appliances to ensure they are safe.
• The Annual Boiler Service: This is your financial duty to your investment. A service ensures the boiler is running at peak efficiency, preventing the build-up of deposits that reduce performance and increase gas consumption. It also catches small faults before they become major, costly breakdowns. The smartest and most cost-effective approach is to book your CP12 and boiler service together in one appointment.

A well-maintained, efficient boiler, paired with a smart zonal control system, is the ultimate combination for a profitable and easy-to-manage HMO. You stop wasting money heating empty rooms, you put a sensible cap on energy usage, and you give tenants the comfort and control they desire. You turn your biggest, most unpredictable cost into a manageable, predictable expense.

If you’re an HMO landlord in London tired of shocking gas bills, it’s time to take back control. Contact Boiler Repairs R US today. We are experts in designing and installing efficient, smart heating systems for the unique demands of HMO properties.

---

---

We specialise in all boiler manufacturers including;

---

---