Shallow vs. deep retrofit: which one is right for you?
In part two of our home retrofitting series, we’re going deeper into retrofitting approaches—this time with expert insights from Munster-based One Stop Shop provider, Insulex.
So, you’ve decided your home needs an energy makeover—but how far should you go? For homeowners looking to cut energy bills and stay warm, the big decision comes down to a shallow retrofit or a deep retrofit.
Each approach has its pros and cons, and the right choice depends on your home, your budget and how much disruption you can handle.
We spoke to home energy upgrade specialist Insulex, to break down the key differences and help you decide which route to take.
What is a shallow retrofit?
Think of a shallow retrofit as giving your home a little TLC. It’s about smaller, less invasive upgrades that you can tackle individually.
According to Insulex’s marketing manager[1] , Bridget O’Sullivan, this approach is ideal if you want to improve your home’s efficiency without a massive upfront investment:
“Shallow retrofitting focuses on the most essential upgrades within a restricted budget. It typically starts with high-impact, lower-cost areas like attic insulation or upgrading your boiler.”
Shallow retrofits often include doing just one or two of the following, but you can take the middle ground and carry out several upgrades over time, or step-by-step:
● Attic or cavity wall insulation
● Draught-proofing
● Fitting solar panels
● Upgrading to a more efficient boiler
● Installing heating controls
● Insulating hot water pipes or adding a cylinder jacket
While the shallow approach is initially cheaper, it can cost more in the long run—especially if you have to redo previous work to meet Ireland’s future energy saving targets. Bridget recommends thinking ahead.
“One of the key considerations if you choose this option is to make sure each step is part of a long-term plan to avoid inefficiencies. For example, installing a heat pump before addressing fundamental heat loss and insulating the home properly.”
What is a deep retrofit?
A deep retrofit is the ultimate energy upgrade. It means transforming multiple aspects of the house all at once to deliver serious energy savings and comfort—from the fabric to ventilation and heating systems.
“The deep retrofit approach, aka The 'Whole Hog' has specific targets that must be achieved in order to access the One Stop Shop grant. For example, post works, we have to deliver a B2 BER rating as a minimum standard.
It usually involves a combination of key measures done at the same time, including insulation, potentially window and door upgrades, in some cases floor insulation is required, upgrading to a renewable heating system and perhaps adding Solar PV.
Naturally, as a result, you will have a higher upfront cost, but you can also access maximum grants and optimise energy savings.”
Deep retrofit measures often include most or all of these:
● External, internal, or floor insulation
● Triple-glazed windows and new doors
● Heat pump installation
● Solar PV panels
● Mechanical ventilation systems
Shallow vs. deep retrofit: at a glance
Criteria
Shallow Retrofit
Deep Retrofit
Cost
Lower upfront costs
Higher upfront costs, larger changes
Energy Savings
Moderate reduction
Maximum energy reduction (30-70%)
Timeframe
Phased over time
Completed in one go (8-12 weeks)
Disruption
Minimal
Significant (especially with insulation
Insurance impact
Some policy updates may be needed
Likely to need a full review of your policy
Which retrofit should you choose?
It really depends on your situation. Here are a few things to keep in mind:
Your budget
Tight on cash? Go shallow and just tackle the essential upgrades or do them step-by-step. Got room for a bigger spend? A deep retrofit maximises grants and long-term savings.
Your home's condition
For basic improvements (like insulation or boiler upgrades), a shallow retrofit equals quick wins. But if you have an older property that loses a lot of heat, a deep retrofit is the most effective, sustainable solution.
Your long-term plan
To future-proof your home and reduce carbon emissions, deep retrofitting aligns with Ireland’s goal of being climate neutral by 2050. But if you’d rather spread both the work and costs over time, a shallow or step-by-step approach fits the bill.
Beware the pitfalls
As Bridget points out, whichever option you choose, a little foresight goes a long way. Try to avoid falling into the trap of these common mistakes and misconceptions:
Underestimating the scope of the grants
“Many homeowners expect grants to cover the entire cost, but deep retrofits still require significant personal investment. Plus, individual grants are not available for window and external door upgrades as a single measure. They’re only available as part of a deep home retrofit under the One Stop Shop grant.”
Confusing a BER with a Home Energy Assessment
“These are fundamentally linked and share similar data but give us different information that’s used for different reasons. A Home Energy Assessment is usually the first step if you are embarking on a deep retrofit of your home or trying to qualify for a One Stop Shop grant, and this will incorporate an up-to-date BER assessment.”
Choosing the wrong contractor
“Not all contractors are experienced with deep retrofits, and some may not be SEAI-registered or approved, leading to potential grant eligibility issues. If you want to get an SEAI grant for home energy upgrades, you need to use an approved, registered SEAI contractor.“
Impact on home insurance
Whether you go shallow or deep, retrofitting affects your home insurance in a few important ways:
● Potential savings—improved energy efficiency can reduce risks like damp and fire, which may lower your premiums.
● Policy updates—major upgrades (like heat pumps or solar panels) need to be reflected in your policy to ensure full coverage.
● Extra coverage—some improvements may require additional protection, for example, solar PV systems.
● Contractor insurance—always ensure your retrofit contractor has public liability and professional indemnity insurance.
At Quote Devil, we help you stay covered as your home evolves. Whether you’re taking baby steps by just adding insulation or going all-in with a deep retrofit, we’ll make sure your insurance policy reflects any upgrades—without overpaying.
What’s next?
Still unsure which type of retrofit is right for you? Our next article will guide you through all things solar power, from installation types to cost considerations and available grants. Whatever your path, Quote Devil is here to make sure your home (and your wallet) is protected every step of the way.
