20-year-old water heater acting up? Dive into real-world facts, costs, safety tips & pro advice to decide whether you should repair or replace your aging water heater.
Water Heater Replacement: How to Know It’s Time and What to Do
Got a water heater that’s getting noisy, rusty, or just not heating water fast enough? Those are the classic red flags that say it’s time for a new unit. In most UK homes a water heater lasts 8‑12 years, so if yours is in that age range and you’re seeing leaks, strange smells, or a sudden rise in your energy bill, start thinking about a swap.
Another easy check is the temperature. If you have to turn the dial up higher than usual and still get lukewarm showers, the heating element is probably on its last legs. Likewise, a buildup of sediment at the bottom of the tank reduces efficiency and can cause the heater to overheat. Flushing the tank helps, but if the sediment is thick you’ll likely need a fresh heater.
Cost and Choosing a New Heater
Replacing a water heater isn’t just a price tag; it’s an investment in comfort and energy savings. A standard electric tank in the UK runs between £400 and £800 for the unit alone, while a gas‑powered model can cost £600‑£1,200. Installation adds another £150‑£300 if you hire a qualified engineer. Getting a few quotes helps you compare not just price but also warranties and service options.
When picking a new heater, think about the size you need. A 150‑litre tank works for a two‑person household, but families of four or more usually need 200‑250 litres. If space is tight, look at slim‑line or “tank‑less” (on‑demand) systems – they’re smaller and heat water only when you need it, which can cut running costs.
Energy efficiency ratings are a must‑check. Look for units with the highest EF (Energy Factor) you can afford; a higher EF means lower monthly bills. Also, consider a model with a stainless‑steel inner tank – it resists corrosion better than the cheaper glass‑lined tanks.
DIY vs Professional Installation
You can handle the basics yourself, like draining the old tank or cleaning the anode rod, but wiring a new electric heater or connecting gas lines is a job for a certified installer. The UK’s Gas Safe Register and Part P electrical rules require a qualified professional for any work that involves gas or high‑voltage circuits. Trying to do it yourself can void warranties and, more importantly, put your home at risk.
If you decide to go the DIY route for the removal, make sure the power is off at the consumer unit and the water supply is shut. Hook up a garden hose to the drain valve, open the valve, and let the water flow out into a bucket or floor drain. Once the old tank is out of the way, you’ll have a clear view of the pipe layout, which makes the installer’s job faster and cheaper.
Finally, schedule a post‑installation check. A good engineer will test the temperature, pressure relief valve, and check for any leaks before they leave. Ask for a copy of the certification and keep it with your other home documents – you’ll need it for future insurance claims or resale.
Replacing a water heater feels like a big step, but with the right signs, a clear budget, and a qualified installer, it’s a smooth process. You’ll enjoy hot water on demand, lower energy bills, and peace of mind knowing the new unit meets today’s safety standards.
Not sure if your hot water heater's on its last legs? This guide breaks down all the warning signs, plus some handy tips to help you know when it’s time for a replacement.