How to Choose a Built-in Microwave (2026 UK Guide)
Built-in microwaves sit in kitchen cabinetry like an oven, not on your worktop. This guide explains what actually matters when choosing one. We're Go Assist Appliances, a UK family-owned retailer backed by 17 years of home service experience across the country. Our engineers install and repair these units daily. We know what breaks, what lasts, and what features get used versus what sits idle.
This guide covers microwave-grill combinations and combi models that add convection oven functions. We'll walk through capacity, power ratings, cavity sizes, and which features justify their price tags.
The 5 Things That Actually Matter
1. Cavity Size and Installation Height
Built-in microwaves come in two standard heights: 385mm and 455mm. The smaller units hold 31 litres. The taller ones hold 40 to 53 litres. If you're replacing an existing unit, measure your cabinet aperture first. A 385mm microwave fits where a standard compact oven goes. A 455mm model needs a full-height oven slot.
Width is standard at 595mm for almost all built-in microwaves. Depth varies by 30mm or so between brands, but any reputable unit will fit a standard 560mm deep cabinet with room for ventilation behind.
2. Microwave Power Output
This number, measured in watts, determines how quickly your food heats. A 900W microwave takes about 4 minutes to heat a bowl of soup. A 1000W model does it in 3.5 minutes. That's the reality of the difference.
Most built-in units sit between 900W and 1000W for microwave function. Higher isn't always better if you mostly reheat leftovers. Lower power gives you finer control for defrosting delicate items like fish or pastry.
3. Grill Versus Combi Functions
A microwave-grill has two heating methods: microwaves from the magnetron and a grill element at the top of the cavity. Good for browning jacket potatoes, crisping bacon, or finishing off a lasagne top. Grill power ranges from 800W to 1600W. Higher wattage means faster browning.
A combi microwave adds a third function: fan-assisted convection like a proper oven. You can bake cakes, roast chicken, or cook frozen pizza. Combi models typically have 2000W total heating power split between upper and lower elements. If your kitchen lacks a second oven, a combi fills that gap.
The trade-off is price. Combi models cost £600 to £900. Microwave-grills cost £380 to £480. Ask yourself how often you'd genuinely bake or roast in this cavity instead of your main oven.
4. Control Layout
Built-in microwaves use touch controls or rotating dials. Touch panels look cleaner but can be fiddly when your hands are wet or floury. Dials give tactile feedback and are faster for quick adjustments.
Pre-set programmes sound helpful but most households settle on three or four functions: reheat, defrost, grill, and maybe one auto-cook setting. Ignore claims of 40 automatic programmes. You won't use them.
5. Interior Coating
Stainless steel interiors wipe clean easily but show splatters. Enamel coatings hide marks better but can chip if you're rough with metal utensils. Some models have catalytic or steam-clean liners that break down grease during a cleaning cycle. These work to a point but you'll still need to wipe surfaces manually.
Hotpoint's Diamond Steam cleaning runs a cycle that loosens baked-on food with steam. It's a time-saver if you cook fatty foods regularly. Not essential, but noticeably easier than scrubbing by hand.
The 3 Things Marketing Will Upsell That Don't Matter Much
1. App Connectivity and Smart Features
Some microwaves connect to your phone for remote start or recipe downloads. In practice, you're standing in the kitchen anyway. Remote start is pointless unless you enjoy cold food that's been sitting for 10 minutes while you finish your commute. Skip this feature unless you're already deep into a smart home setup and genuinely use every connected device.
2. Excessive Auto-Cook Menus
A microwave with 30 pre-programmed settings sounds versatile. In reality, most people use manual power levels and timers. Auto-cook menus rely on average food weights and starting temperatures. Your leftover curry from the fridge won't match the programme's assumptions. You'll learn your own timings within a week of ownership.
3. Cosmetic Trim Kits
Manufacturers sell trim kits to make the microwave sit flush with cabinets. They're aesthetic, not functional. Standard built-in models already have a finished front that sits flat against your cabinet face. A trim kit adds £50 to £100 for a 10mm frame. Only consider this if your kitchen has zero tolerance for visible cabinet edges.
How to Pick the Right Capacity for Your Household
A 31-litre cavity suits one or two people. You can fit a 10-inch dinner plate or a medium casserole dish. If you regularly cook for three or more, or if you batch-cook and reheat family portions, get 40 litres minimum.
Combi models with 53 litres give you space for a small roasting tin or a 12-inch pizza. This size makes sense if you're using the convection oven function regularly. For microwave-only use, 53 litres is overkill and you'll pay for unused space.
Check the turntable diameter if you have oversized plates. A 31-litre cavity typically has a 315mm turntable. Large dinner plates (280mm to 300mm) fit with a few millimetres to spare. If your plates are bigger, measure first.
Energy Rating Reality Check
Built-in microwaves show energy labels from A to G for the oven function. The microwave function uses negligible electricity regardless of rating. A 1000W microwave running for 5 minutes uses 0.08 kWh. At 24p per kWh, that's under 2p per use.
The oven function consumes more. A B-rated combi microwave uses roughly 0.8 kWh per hour of convection cooking. A D-rated model uses 1.0 kWh. The difference is £12 per year if you use the oven function for an hour every week. Over five years that's £60. Factor this into your buying decision but don't let it override more important features like capacity or reliability.
Standby power is under 1W for modern models. You're spending under £2 per year leaving it plugged in.
Reliability Signals to Look For
Brand matters less than specific model track records, but some patterns hold. Hotpoint and Whirlpool dominate the UK built-in microwave market. Both have widespread parts availability and repairable designs. We rarely see catastrophic failures in either brand's mid-range models.
Warranty length signals manufacturer confidence. Most built-in microwaves carry a 12-month parts and labour warranty. That's standard. Anything less is a red flag. Extended warranties are available but usually poor value. Put the £80 premium towards a better model instead.
Check if replacement parts like turntables, glass trays, and door seals are available separately. Whirlpool and Hotpoint stock these for at least 7 years after discontinuation. Budget brands often stop parts supply within 3 years.
Avoid units with proprietary control boards sealed in resin. If the electronics fail, you're replacing the entire board at £150 to £200 instead of a £40 relay or £60 touchpad. This is rare in quality brands but common in supermarket own-label products.
Our Picks from Current Stock
Hotpoint HMD44MBUK (£383): 31-litre microwave-grill at 385mm height, 1000W microwave and 800W grill. Best for compact spaces or single-oven kitchens where you need basic grilling but not full convection. Black finish hides fingerprints better than stainless.
Whirlpool WMD54MXUK (£419): Another 385mm unit with 31 litres and grill. Whirlpool's build quality edges ahead of the equivalent Hotpoint for an extra £36. Worth it if you plan to keep this for 10 years.
Whirlpool WCW7O7HTSBUK (£686): 455mm combi with 53 litres, 950W microwave and 2000W convection. This is a second oven that happens to have a microwave. Good if you're serious about using the oven function weekly.
Hotpoint HCW9OWPHTSBUK (£757): 53-litre combi at 455mm, 2000W convection with Hotpoint's Cook3 function that runs three cooking stages sequentially. Useful if you're reheating complex dishes that need defrost, then microwave, then grill. Niche but effective.
Hotpoint HCT9A9PHTSBUK (£889): Top of our range. 53 litres, 455mm, 2000W convection plus steam injection for bread and pastry. Diamond steam cleaning included. Only justifiable if you bake regularly and want steam for crust development. Expensive for a microwave, reasonable for a capable second oven.
Ready to Choose?
Every appliance in our range carries the manufacturer's warranty and our 14-day returns policy. We're UK family-owned, based in Bournemouth, with support staff who actually understand the products. Browse our built-in microwave collection and filter by size or budget. If you're unsure which model fits your cabinet, call us before ordering.
This guide was last updated on 10 April 2026. Prices and stock states change daily — check the linked product pages for the current position. Got a question an engineer should answer? Drop us a line.
