Choosing a new boiler isn’t something most people do every day — and if you’re anything like most of our customers here at EPM, you’re probably thinking:
“I just want something reliable, efficient, and that won’t cost me a fortune.”
But then you’re faced with two options: combi boiler or system boiler.
So what’s the difference? And which one is right for your home?
Let’s break it down — simply, honestly, and from the perspective of someone who installs both types across Exeter and the South West every week.
First, What’s the Real Difference Between a Combi and a System Boiler?
Here’s the short version:
Feature | Combi Boiler | System Boiler |
Heats water on demand? | ✅ Yes | ❌ No (uses cylinder) |
Needs hot water cylinder? | ❌ No | ✅ Yes |
Good for multiple bathrooms? | 🚫 Not ideal | ✅ Yes |
Space saving? | ✅ Best option | ❌ Needs more room |
Mains pressure hot water? | ✅ Yes | ✅ Yes |
Which Is Best for Your Home?
Let’s go beyond the technical stuff — here’s what we ask customers when helping them choose:
- How Many People Live in Your Home?
- 1–2 people, 1 bathroom?
✅ Combi is usually perfect. Heats water as needed, no storage tank, and saves space. - Family of 4+, multiple bathrooms or en-suites?
✅ System boiler handles demand better. It stores hot water in a cylinder so multiple showers can run at once — no “cold shower surprise.”
- Is Space an Issue?
Live in a flat or smaller house with no airing cupboard or loft space?
👉 A combi boiler is a no-brainer. It’s compact, wall-mounted, and doesn’t need a hot water tank.
On the other hand, if you’ve already got a cylinder and space to keep it, a system boiler can be just as efficient — and more comfortable if you’ve got a busy household.
- Do You Want Instant Hot Water, Anytime?
- Combi boilers give you hot water on demand.
No waiting for tanks to heat up. It’s just: tap on — hot water. - System boilers rely on a hot water cylinder.
That means when it’s empty, you’ll need to wait for it to heat again. Fine if you plan around it — but not ideal if your teenager takes 45-minute showers.
- Do You Have Low Water Pressure?
Neither combi nor system boilers will solve this if your mains water pressure is poor — but we always test this before recommending a new setup.
⚠️ Combi boilers rely on good mains pressure for decent showers and tap flow. If it’s low, we may recommend adding a pump or going with a pressurised system boiler setup instead.
- Do You Want to Futureproof for Solar or Heat Pumps?
Planning for solar thermal or other energy upgrades?
✅ A system boiler with a unvented cylinder is usually easier to adapt.
We’re always happy to talk futureproofing — even if you’re not planning it just yet. A little prep now saves money later.
Quick Pros & Cons Summary
✅ Combi Boiler Pros:
- Space-saving
- Hot water on demand
- More efficient for smaller homes
- No need for a separate tank or cylinder
- Often cheaper to install
❌ Combi Cons:
- Can’t run multiple showers easily
- Slower flow rate if demand is high
- Not ideal in low-pressure areas
✅ System Boiler Pros:
- Handles multiple bathrooms well
- Better flow rates for bigger homes
- Works well with solar/heat pump systems
- More consistent hot water in busy households
❌ System Cons:
- Needs more space (tank + boiler)
- Hot water isn’t instant (relies on cylinder)
- Slightly higher install cost
So — Which Boiler Do We Recommend at EPM?
Here’s the honest truth:
There’s no “best” boiler for everyone. It comes down to your home, your needs, and your budget.
What we do at EPM is visit your property (free of charge), ask the right questions, and give you a straight, no-jargon recommendation — often with multiple price options.
We install both combis and system boilers all across Exeter, and we’ll always explain why we’re suggesting one over the other.
Final Word
If you’re still not sure, don’t worry — you’re not alone. This is one of the most common decisions homeowners face when upgrading their heating system.
Need honest advice or a boiler estimate? If you’re in Exeter or nearby, give us a ring or fill in our quick online form. We’re local, Gas Safe registered, and we won’t talk you into something you don’t need.
📞 Call EPM today or complete an online form — we’re happy to help, no pressure.
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