So you're thinking about installing a heat pump. Smart move. I did mine three years ago after my ancient furnace gave up the ghost during that brutal February cold snap. Best decision I made for my home and energy bills – but man, I wish I'd known half this stuff beforehand. That's why I'm writing this: to save you the headaches I went through.
Why Bother With a Heat Pump Anyway?
Heat pumps aren't some sci-fi gadget anymore. They're mainstream because they work. Instead of burning fuel to create heat, they move existing warmth from outside air into your home (yes, even when it's freezing). My neighbor Paul was skeptical until he saw my January utility bill – $127 versus his $290 gas bill for the same size house.
Quick reality check: These aren't magic boxes. In extreme cold (we're talking -20°C/-4°F), efficiency drops. That's why I kept my existing radiators as backup. But for 95% of winter days? Pure gold.
Heat Pump Types Explained (No Marketing Fluff)
Picking the right type makes or breaks your experience:
| Type | Best For | Installation Hassle | Ballpark Cost |
|---|---|---|---|
| Air-to-Air | Homes with ductwork already | ⭐ (Easiest) | £5,000-£8,000 |
| Air-to-Water | Radiator/underfloor heating systems | ⭐⭐⭐ (Moderate) | £7,000-£12,000 |
| Ground Source | Rural properties with land | ⭐⭐⭐⭐⭐ (Complex) | £14,000-£24,000 |
Tried ground source at my cousin's farmhouse. Works brilliantly but the trench digging? Never again. For most suburban homes, air-to-water is the sweet spot.
The Pre-Installation Game Plan
Jumping straight into how to fit a heat pump without prep is like baking a cake without checking your ingredients. Here's what actually matters:
- Insulation Audit: Got drafty windows or an uninsulated loft? Fix those FIRST. I wasted £800 on oversized equipment because my installer didn't check this.
- Heating Load Calculation: Not some abstract concept – it determines your unit size. My first quote was for a 16kW monster. After proper calcs? 12kW was perfect.
- Electrical Check: Older homes might need panel upgrades. My 1960s bungalow required a new consumer unit (£420).
Watch out: Skip any installer who eyeballs your unit size instead of doing Manual J calculations. That oversized unit will short-cycle and die early.
Step-by-Step: How to Fit a Heat Pump (The Real Process)
Okay, let's get into the actual heat pump fitting process. This is based on my second (successful!) installation:
1. The Site Assessment
Two guys spent three hours measuring every room, checking windows, even peeking in the attic. Good sign. They rejected my preferred outdoor spot (too close to bedroom windows – noise issues). Annoying then, brilliant now.
2. The Installation Week
- Day 1: Outdoor unit pad poured (concrete slab 30cm thick)
- Day 2: Pipework run through utility room (annoying dust, but tidy work)
- Day 3: Indoor unit installed and linked to existing radiators
- Day 4: Electrical connections and system flush
- Day 5: Commissioning and handover tutorial
The mess was minimal, but they did scratch my hallway flooring. Lesson: Cover EVERYTHING yourself beforehand.
3. The Commissioning Drama
Don't let them leave until they've:
- Shown you how to operate the thermostat (mine has 87 settings – seriously)
- Tested heating AND cooling modes
- Given written flow temperature settings (crucial for efficiency)
My first install failed here. The unit ran constantly because flow temps were set wrong.
Equipment Costs vs. Lifetime Savings
Let's talk money. Yeah, it's steep upfront, but the math works:
| Expense | My Cost (3-bed semi) | Savings Offset |
|---|---|---|
| Daikin Altherma 11kW unit | £6,200 | £1,280/year vs old gas boiler (Break-even in ~6 years) |
| Installation labour | £2,800 | |
| Electrical upgrades | £420 | |
| Government grant (BUS) | -£5,000 | |
| TOTAL OUTLAY | £4,420 |
Finding Your Installer: Red Flags Checklist
After two experiences, here's what I look for:
- ✅ MCS Certification (non-negotiable for grants)
- ✅ Specific heat pump training badges (look for manufacturer logos)
- ✅ Willingness to share past customer contacts
- 🚩 Quotes under £7k for full system (probably cutting corners)
- 🚩 Pushy sales tactics ("limited time offer")
Post-Installation: What Nobody Tells You
Congrats! Now the real work begins:
Operation Settings That Matter
- Flow Temperatures: Keep below 50°C for optimal efficiency. Mine runs at 45°C.
- Weather Compensation: MUST be enabled. Lets the system adjust automatically.
- Timers Suck: Constant low heat beats aggressive cycling. I set mine to 19°C 24/7.
Maintenance Reality Check
Forget annual £90 boiler services. But:
- Monthly: Clean outdoor unit coils (hose down)
- Bi-annual: Check refrigerant pressure (DIY gauges cost £30)
- Every 3 years: Professional system check (£70-£120)
My installer forgot to mention the coil cleaning. First winter's efficiency dropped 15% until I figured it out.
Top Mistakes When Fitting Heat Pumps (Save Yourself!)
Watching forums daily, I see these repeatedly:
| Mistake | Consequence | How to Avoid |
|---|---|---|
| Oversized units | Short cycling, noise, early failure | Demand heat load calculations |
| Bad outdoor placement | Vibration noise, reduced airflow | Min. 30cm clearance all sides |
| Ignoring radiator upgrades | Poor heat distribution, high flow temps | Replace any radiators over 15 yrs old |
My mistake? Not insulating refrigerant lines properly. Condensation dripped through my ceiling. £380 repair bill.
Heat Pump FAQ: Real Questions From Homeowners
Do I need underfloor heating?
Nope. My 1950s radiators work fine. But I did replace three small upstairs ones (£160 each) because they couldn't output enough heat at lower temps.
How noisy is it REALLY?
At 1 meter distance, my Mitsubishi runs at 42dB – like a quiet fridge. But mount it on a flimsy wall? Whole house vibrates. Proper mounting matters more than specs.
Can it handle UK winters?
Yes, but with caveats. Below -5°C, efficiency drops. Solution: I set mine to switch automatically to my immersion heater below that temp. Added £40/year to bills.
What about cooling in summer?
Game-changer. My bedroom stays at 22°C during heatwaves for about 30p/day. But you MUST specify this at installation – retrofitting is messy.
How long do they actually last?
My installer's oldest unit is 17 years and counting. But compressors typically need replacing around year 12-15 (£800-£1,200). Still cheaper than new boilers every 10 years.
Is Fitting a Heat Pump Worth It For You?
Honestly? It depends. If you:
- Live in a well-insulated home (EPC C or above)
- Have £4k-£9k after grants available
- Plan to stay put 7+ years
...then absolutely. My only regret is not doing it sooner.
But if your house is draughty or you're moving soon? Maybe wait. The process isn't trivial – it demands research and vigilance. When done right though? Nothing beats walking around in a t-shirt in January while your neighbors shovel snow off their driveways.
Final Pro Tips
- Photograph EVERYTHING before walls are closed up (pipe routes, wiring)
- Demand the commissioning report in writing
- Join Heat Geek's Facebook group – saved me £400 on settings tweaks
Still feeling overwhelmed? Just remember: thousands of us figured out how to fit a heat pump successfully. With the right prep, you absolutely can too. Might even enjoy those lower bills as much as I do.
Leave A Comment