How We Slashed Our Heating Bills: Complete Home Heating Upgrade Journey

Why We Needed to Act

Our four-bedroom detached house was hemorrhaging heat - and money. We had:

• An ancient Potterton Netaheat boiler that was inefficient and unreliable
• Old wooden door with a letterbox creating arctic draughts
• Original windows that barely qualified as "double glazing"
• Central heating pipework from the copper shortage era - compression fittings on chrome pipes
• Inadequate loft insulation
• No control optimization - just an on/off thermostat

Our heating bills were painful, but worse, the house never felt truly warm. You could feel cold air blowing through gaps around the front door. Radiators took ages to heat up. The boiler clanked and groaned.

We knew we had to fix it, but the question was: where to start?

The Strategy: Insulate First, Upgrade Second, Optimize Last

We didn't do everything at once (neither our budget nor our sanity could handle that). Instead, we followed the classic energy efficiency hierarchy:

1. Stop heat escaping - Draught-proofing, insulation, better windows
2. Improve heat generation - Modern boiler and radiator system
3. Optimize control - Smart heating curves and outdoor compensation

This order is critical. There's no point installing an efficient boiler if half the heat escapes through the roof. Conversely, you can't optimize what doesn't work properly in the first place.

Step 1: Quick Wins - Draught-Proofing

We started with the cheapest, fastest improvements:

The Letterbox Problem

Our old wooden front door had a traditional letterbox that created a significant draught. Every winter, you could feel cold air pouring through it. My solution was hilariously low-tech but effective: block it with a piece of wood at night, remove it before the postman came in the morning.

Did this work? Absolutely. Was it sustainable? Absolutely not. Eventually, we replaced the door entirely (more on that below), but for months, this £0 solution made a noticeable difference.

Thermal Curtains

We installed a heavy thermal curtain across the hallway near the front door. This created an airlock effect, preventing draughts from sweeping through the entire ground floor.

Cost: minimal. Impact: immediate. If you have a draughty entrance, do this today.

Step 2: Loft Insulation - The Forgotten Space

Heat rises. If your loft isn't properly insulated, you're literally heating the sky. Our loft had some insulation, but it was thin, patchy, and decades old.

We topped it up to modern standards. The difference was immediate - the upstairs bedrooms stayed warmer for longer, and the heating didn't need to run as constantly.

This is one of those upgrades where the payback period is measured in months, not years. If your loft insulation is lacking, fix it before anything else.

📝 Detailed article coming soon: Loft insulation installation, costs, and lessons learned.

Step 3: Windows & Doors - Stopping the Leaks

Our original windows were technically "double glazed," but they were old, inefficient, and had noticeable gaps around the frames. The front door, as mentioned, was a wooden draughtmaker with a letterbox that might as well have been an open window.

We replaced everything with modern, energy-rated double glazing and a proper insulated front door with integrated letterbox draught-proofing (no more wooden blocks required!).

The house became noticeably quieter and warmer. Condensation on windows reduced dramatically. The difference was night and day.

📝 Detailed article coming soon: Window replacement costs, energy ratings, and whether it's worth it.

Step 4: Complete Central Heating System Replacement

Here's where things got serious. Our house was built during a copper shortage, which meant the original central heating used compression fittings on chrome-looking pipes instead of proper copper pipework.

These fittings were prone to leaks, inefficient, and frankly, a relic of cost-cutting construction practices. We decided to rip it all out and start fresh:

• All new copper pipework throughout the house
• New radiators properly sized for each room
• Proper balancing to ensure even heat distribution

This was a major undertaking, but it transformed the heating system from "it sort of works" to "it works properly." No more cold spots, no more banging pipes, no more leaks.

📝 Detailed article coming soon: Central heating replacement - costs, DIY vs professional, and lessons learned.

Step 5: Boiler Replacement - Potterton Netaheat to Vaillant Ecotech Plus

With everything else upgraded, it was finally time to replace the boiler itself. Our ancient Potterton Netaheat was:

• Inefficient (probably around 70% efficiency vs. modern 90%+)
• Unreliable (annual breakdowns were expected)
• Non-condensing (wasting energy through the flue)
• Noisy (clanking, groaning, general distress sounds)

Why We Chose the Vaillant Ecotech Plus

After researching extensively, we selected the Vaillant Ecotech Plus for several reasons:

• Efficiency: Over 90% efficiency when running in condensing mode
• Reliability: Vaillant's reputation for longevity
• Modulation: Can adjust output smoothly rather than on/off cycling
• Weather Compensation: Works with outdoor sensors for optimal efficiency
• Build Quality: German engineering, proven track record

The installation was straightforward (helped by having all-new pipework), and the difference was immediate. The house heated faster, more evenly, and far more quietly.

📝 Detailed article coming soon: Why we chose Vaillant Ecotech Plus, installation costs, and first-year performance.

Step 6: The Secret Sauce - Heat Curve Optimization

This is where it gets interesting. Most people install a new boiler and never touch the advanced settings. They run it like their old boiler - full blast when cold, off when warm. This is inefficient and uncomfortable.

Modern condensing boilers like the Vaillant work best when run "low and slow" - like a slow cooker rather than a microwave. To achieve this, we installed a Glowworm outdoor sensor and carefully adjusted the heat curve.

What is a Heat Curve?

A heat curve defines the relationship between outdoor temperature and the water temperature your boiler produces. When it's freezing outside, you need hotter water in the radiators. When it's mild, you need cooler water.

By tuning this curve, you can:

• Keep the boiler running in condensing mode (maximum efficiency)
• Maintain steady indoor temperatures without dramatic swings
• Reduce boiler cycling (which wears components and wastes energy)
• Lower gas consumption significantly

How We Set It Up

We installed the outdoor sensor on a north-facing wall (away from direct sunlight). Then we adjusted the heat curve gradually over several weeks, monitoring:

• Indoor temperatures at different outdoor temperatures
• Whether the boiler stayed in condensing mode (flue condensate check)
• Gas consumption via our smart meter
• Comfort levels throughout the day

The result? The boiler now runs almost continuously at low output, maintaining a steady 20-21°C throughout the house with minimal cycling. It's gentler on the boiler, more efficient, and more comfortable.

📝 Detailed article coming soon: Heat curve setup guide, outdoor sensor installation, and optimization tips.

The Results: Was It Worth It?

Comfort

The house is noticeably warmer and more comfortable. No draughts, no cold spots, no temperature swings. It just maintains a steady, pleasant temperature.

Energy Bills

Exact figures vary with gas prices, but our consumption dropped significantly. The combination of insulation, modern windows, an efficient boiler, and optimized controls means we heat a much better-sealed house with far less energy.

Maintenance

The old Potterton needed annual repairs. The Vaillant has run flawlessly since installation, requiring only annual servicing.

Value

Home improvements like these add genuine value to your property. Energy efficiency is increasingly important to buyers, and a modern heating system is a major selling point.

Key Lessons Learned

1. Insulate Before You Upgrade

Don't buy a bigger boiler to heat a leaky house. Fix the leaks first, then right-size your heating system for the actual heat loss.

2. Cheap Fixes Buy You Time

Blocking that letterbox with wood was ridiculous, but it worked while we saved for the door replacement. Don't be too proud for temporary solutions.

3. Do It In The Right Order

We're glad we did loft insulation and windows before replacing the boiler. It meant we could install a smaller, cheaper boiler that still kept the house warm.

4. Optimization Matters As Much As Hardware

The heat curve tuning probably saved us as much money as the boiler upgrade itself. Don't install a modern boiler and run it like an old one.

5. Take Photos

We documented everything with photos. This helped with insurance, proved to buyers what we'd done, and made writing these articles much easier!

Detailed Articles Coming Soon

This overview scratches the surface. Over the coming weeks, I'll be publishing detailed articles on each stage:

Final Thoughts

Transforming our heating system from inefficient and uncomfortable to optimized and economical took time, money, and plenty of research. But it was absolutely worth it.

Our house is warmer, our bills are lower, and we're no longer dreading winter. The combination of insulation, modern equipment, and smart optimization means we're heating efficiently rather than just heating expensively.

If you're facing similar challenges, start with the cheap fixes (draught-proofing, loft insulation), then work your way up to the bigger upgrades. And when you finally install that new boiler, please take the time to optimize it properly. That's where the real savings live.

I'll be publishing the detailed articles over the coming weeks. Each will include photos, costs, and practical lessons learned. If there's a specific topic you want covered first, let me know!