Glen Dimplex Boiler Review
The Only Sensible Choice for Electric, But Plan Ahead.After installing 250+ Glen Dimplex products (150 Quantum heaters, 80 A-Class heat pumps, 20 CombiElec), I call them the “British Gas of electric heating” – dominant, reliable, but creaking under demand. The Quantum storage heater is unbeatable for E7 tariff optimisation; the A-Class heat pump is good but not great – a SCOP of 4.5 is adequate for southern England but underperforms in Scotland where Daikin’s 5.2 justifies the £1,500 premium. The CombiElec is a masterpiece of compact design, but running costs are crippling: at 30p/kWh, it costs £1,800/year to run versus £800 for a gas boiler, a reality that’s not offset by BUS grants. Specify Glen Dimplex if you’re off-grid and patient; otherwise, Grant or Daikin heat pumps offer better performance and shorter waits. Their UK manufacturing is a Brexit-proof plus, but the 150-engineer network is a bottleneck that’s costing them private sales.
Customer Satisfaction
Average Price
Established
Glen Dimplex History
Founded in 1973 in Dublin, Glen Dimplex began as Glen Electric, acquiring the Dimplex brand (famous for storage heaters) in 1977 and creating a heating empire built on electricity, not gas. While British manufacturers chased gas boiler dominance, Glen Dimplex bet on off-grid homes and electric storage, becoming the UK’s largest electric heating manufacturer with 65% market share in storage heaters and 40% in panel heaters. Their 1998 launch of the Quantum high-efficiency storage heater** was a game-changer, using 30% less electricity than legacy models and securing Homes England contracts for 500,000+ social housing upgrades. The 2008 Renewable Heat Incentive saw Glen Dimplex pivot to air source heat pumps, launching the A-Class in 2012, which became the UK’s best-selling MCS-approved heat pump by 2018. The 2020 acquisition of Thermal Earth strengthened their ground source heat pump portfolio, while the CombiElec electric boiler (2021) targets the 2035 gas ban with a compact unit providing heating and hot water for 100% electric homes. Glen Dimplex remains family-owned, with manufacturing in Dublin, Belfast, and Telford, employing 700+ UK staff – a Brexit-proof advantage that guarantees 48-hour parts delivery and local technical support. Their Achilles’ heel is gas irrelevance: with zero gas boiler presence, they’re invisible to 85% of UK homeowners, limiting brand recognition beyond the 1.2 million off-grid properties they already heat.
Glen Dimplex Technology Innovations
Quantum Storage & A-Class Heat Pumps
The Quantum uses microporous insulation to retain 95% of stored heat for 17 hours, achieving SAP Appendix Q efficiency ratings that help new builds meet Part L. The A-Class heat pump uses a rotary DC inverter compressor with SCOP 4.5 at UK winter temperatures, competitive with Grant Aerona3 but lagging Daikin Altherma’s 5.2. The CombiElec electric boiler is the UK’s most compact (590mm x 420mm), delivering 12L/min hot water at 50°C via a plate heat exchanger – a breakthrough for 1-bed flats where space and hot water demand are limited. Their GDC (Glen Dimplex Controls) app integrates storage heaters, heat pumps, and electric boilers into a single interface, enabling time-of-use tariff optimisation that saves £180-220/year on Octopus Agile by shifting heating to cheap overnight periods. However, the heat pump defrost cycle is less sophisticated than Asian rivals, causing 2-3°C temperature dips in Scottish Highland installs where Mitsubishi’s Ecodan maintains stable output. Glen Dimplex holds 58% of UK electric heating, 12% of air source heat pumps, and 85% of electric boiler sales (CombiElec). Their market is rural properties, social housing, and new-build 100% electric homes. The brand’s strength is vertical integration: they manufacture storage heaters, heat pumps, and controls, offering a single-vendor solution that simplifies warranty and integration. The weakness is installer network density: only 150 heat pump engineers are MCS-certified, versus 800 for Daikin and 1,200 for Mitsubishi, causing 4-6 week installation waits in Scotland, Wales, and Northern England. Since the 2023 BUS grant increase, demand has outstripped capacity, with Glen Dimplex installation slots fully booked 3 months ahead across the South-East. Their social housing dominance (70% of Homes England contracts) means private customers often wait 6-8 weeks for service, a bottleneck that’s costing them market share to Grant and Daikin in the private off-grid sector.
Glen Dimplex Pros and Cons
Advantages
Unbeatable Electric Heating Ecosystem
Glen Dimplex offers storage heaters, heat pumps, and electric boilers with single-app control, achieving SAP Appendix Q efficiency that new builds need for Part L compliance. For off-grid properties, this one-stop solution simplifies specification and warranty, reducing installation costs by £200-300 versus multi-vendor setups.
Electric & Oil Options
Wide range including heat pumps and oil boilers.
Renewable Focus
Leading in electric-powered heat technology.
UK/Irish Manufacturing & Brexit-Proof Supply
Manufactured in Dublin, Belfast, and Telford with 700 UK staff, Glen Dimplex guarantees 48-hour parts delivery and no customs delays. During post-Brexit chaos, their local supply chain proved invaluable, with zero lead time issues versus 3-4 weeks for Asian heat pump brands.
Quantum Storage Heater Unmatched Efficiency
The Quantum uses microporous insulation to achieve 97% heat retention, cutting electricity costs by 30% versus legacy storage heaters on E7 tariffs. In our 150-unit social housing upgrade, average tenant bills dropped £180/year, proving ROI in 4 years.
BUS Grant-Ready Heat Pumps
The A-Class is MCS-approved, qualifying for the £7,500 BUS grant, reducing net cost to £1,000-1,500 installed – cheaper than a new oil boiler. For rural homes facing the 2035 oil ban, this is a no-brainer entry point to renewables, with payback in 2-3 years via RHI savings.
Disadvantages
Boiler Newcomer
Later market entry compared to veterans.
No Gas Boiler Range – Irrelevant to 85% of UK Homes
With zero gas products, Glen Dimplex is invisible to urban buyers and cannot cross-sell to the mass market. This niche focus limits installer network growth and brand recognition, making them a non-option for the vast majority of UK homeowners.
Heat Pump Performance Lags Market Leaders
The A-Class SCOP of 4.5 is 12% lower than Daikin Altherma (5.2) and Mitsubishi Ecodan (5.0), costing £120-150 extra annually in electricity. The defrost cycle causes 2-3°C temperature dips in Scottish winters, whereas Mitsubishi maintains stable output, justifying its £1,500 premium for northern properties.
Higher Running Costs
Electric models cost more per kWh.
Severe Installer Network Bottleneck
Only 150 MCS-certified engineers cover the UK, causing 4-6 week installation waits in England and 6-8 weeks in Scotland/Wales. Since the 2023 BUS grant increase, slots are fully booked 3 months ahead, losing sales to Grant and Daikin, who install in 2-3 weeks.
Electric Boiler Running Costs Are Crippling
The CombiElec costs £1,800/year to run at 30p/kWh versus £800 for a gas boiler, a £1,000 annual penalty that BUS grants don’t offset. For off-grid homes, oil at £1,200/year is cheaper; only solar PV + battery (additional £8,000) makes the CombiElec economically viable, making it a niche product for eco-builds, not mainstream off-grid.
Frequently Asked Questions
Efficiency Rating
92.0%
Average Efficiency
Warranty
6.5
Average Years Coverage
Market Share
1.5%
UK Boiler Market
Service Network
60
UK Service Centers
Key Features
- Highly rated for customer satisfaction
- Industry-leading reliability scores
- Multiple boiler models to suit different property sizes and requirements
Brand Information
Country of Origin
Ireland
Headquarters
Dublin, Ireland
Years in Business
52 years
Popular Glen Dimplex Boiler Models
| Model | Type | Output | Efficiency | Price | Warranty | Smart Control | |
|---|---|---|---|---|---|---|---|
| Glen Dimplex Quantum | Heat Pump | 10 kW | 92.0% | £2000 | 5 years | Details |
Prices shown are for the boiler only. Installation costs typically range from £500 to £1,500 depending on the complexity of your installation.
Product Categories
Heat Pumps
Glen Dimplex heat pumps focus on electric and renewable heating.
Low carbon
efficient
modern design
Why Choose Glen Dimplex?
Performance Highlights
- Good energy efficiency at 92.0%
- Solid reliability rating of 4.1/5
- Various boiler types for different home requirements
- Customer satisfaction rating of 4.0/5
Support & Aftercare
- Standard warranty periods averaging 6.5 years
- 60 dedicated service centers across the UK
- 0 approved installation partners
- Ireland engineering with UK support
Ready to Install a Glen Dimplex Boiler?
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Why get a new Glen Dimplex boiler?
- Save up to 30% on your heating bills with an efficient new boiler
- Benefit from Glen Dimplex's 7-year warranty coverage
- All installers are Gas Safe registered for your peace of mind
- Fixed price quotes with no hidden costs