Sources: Ofgem LA guidance v3.0, sections 7-8. Checked 30 October 2026.
Route 3: the four medical categories
Ofgem's guidance says households with a person suffering from a severe or long-term health condition that is adversely affected by living in a cold home are eligible via Flex Route 3. The condition must be due to one of four things:
| Route 3 category | Examples people often ask about* |
|---|---|
| A cardiovascular condition | Heart and circulatory conditions |
| A respiratory disease | Long-term lung and breathing conditions |
| Limited mobility | Conditions that keep someone at home or less active |
| Immunosuppression | Conditions or treatments that weaken the immune system |
*Plain-English descriptions to help you recognise the category. They are not an official list; your GP or NHS clinician decides whether to refer.
Who can refer you, and how
The council can only declare a Route 3 household eligible after a referral from one of these:
- a person on the General Practitioner Register (any GP, NHS or private);
- a Scottish Health Board or a Welsh Health Board;
- an NHS Trust or NHS Foundation Trust (for example a hospital clinician).
The referral must come either as an email from a valid NHS address, or as a letter on headed paper identifying the practice, clinic or hospital (with a GP surgery stamp where relevant), stating that someone in the household has one of the four conditions. Ofgem publishes an NHS referral letter template, though health providers can use their own.
Route 2: health as one of two proxies
Route 2 works differently. You need two of seven proxies, and proxy 3 is vulnerability to the cold under NICE guideline NG6, for a reason other than low income. That list is wider than Route 3:
- cardiovascular or respiratory conditions;
- mental health conditions;
- disabilities;
- older age (65 and over);
- caring for young children, from newborn to school age;
- pregnancy.
Evidence can be a signed letter from a doctor or other health professional sent from an NHS email address, or documents such as an NHS Summary Care Record stamped by the GP practice, a hospital diagnosis letter or repeat prescriptions (cardiovascular and respiratory), a PIP, DLA or Attendance Allowance award notice (disability), or a passport or birth certificate (age 65+). You then need one more proxy, such as a low-income Council Tax reduction. Note that a deprived-area proxy cannot be paired with this health proxy. The full proxy list is on our LA Flex scheme page.
Route 2 or Route 3?
| Route 3 (medical referral) | Route 2 (NICE proxy) | |
|---|---|---|
| Conditions | Cardiovascular, respiratory, limited mobility, immunosuppression | Wider: also mental health, disability, 65+, young children, pregnancy |
| Evidence | NHS referral (GP, Health Board or NHS Trust) | Health letter or documents such as PIP/DLA/Attendance Allowance |
| Anything else needed? | No second test | A second proxy |
| EPC band (owner-occupied) | D to G | E to G |
Steps
- Check your council runs ECO4 Flex and read its Statement of Intent.
- Ask your GP or clinician whether they will make an ECO4 Flex referral (Route 3), or gather the Route 2 documents.
- Check your EPC band; a home rated C or better will not qualify.
- Contact the council or an ECO installer as the Statement of Intent describes. A supplier still decides what to fund.
ECO4 runs until 31 December 2026 (see is ECO4 still available). Use the checker on this page (answer "no" to benefits and choose the health option) or read the full ECO4 eligibility rules.
Questions
What health conditions qualify for ECO4?
Under ECO4 Flex Route 3, a severe or long-term health condition made worse by a cold home, due to a cardiovascular condition, a respiratory disease, limited mobility or immunosuppression, with an NHS referral.
Does COPD or asthma count for ECO4?
Respiratory disease is one of the four Route 3 categories. Whether a particular person qualifies depends on their GP or NHS referral and the council's declaration.
Do I need a letter from my GP for ECO4?
For Route 3, the council needs a referral from a GP, a Scottish or Welsh Health Board, or an NHS Trust, sent from an NHS email or on headed paper. Ofgem publishes a referral letter template.
Does a disability count for ECO4?
Under Route 2, disability is one of the NICE cold-vulnerability reasons for proxy 3, evidenced for example by a PIP, DLA or Attendance Allowance award notice. A second proxy is also needed.