End Feed vs Compression Fittings for Copper Pipe: Which to Use?

When you're running copper pipework, the choice between end feed and compression fittings comes up on every job. It's not a matter of one being better than the other — it's a matter of using the right fitting for the situation. This guide covers when to solder, when to compress, how the two systems compare on cost and reliability, and what we stock at APM Electricals in Acton, West London.

End Feed vs Compression: The Core Difference

The fundamental difference is how the joint is made and sealed:

• End feed fittings — soldered joints. The fitting is pushed onto the pipe and solder is fed into the joint with a torch. The heat draws the solder into the capillary gap by capillary action, creating a permanent, leak-free bond when done correctly. The fitting itself contains no solder — you feed it in externally.
• Compression fittings — mechanical joints. An olive (ferrule) is compressed between the fitting body and a nut by tightening. No heat required. The joint can theoretically be undone and remade, though olives typically deform on first use and aren't reliably reusable.

There's a third type worth knowing — solder ring fittings (also called Yorkshire fittings) — which work the same way as end feed but come with a pre-loaded ring of solder inside the fitting. You apply heat and the solder flows automatically. Slightly more foolproof than end feed for less experienced solderers, but you lose control over the volume of solder applied.

When to Use End Feed Fittings

End feed is the standard choice for the vast majority of copper pipework. It produces a clean, permanent, low-profile joint that sits flush with the pipe. On a full installation — central heating pipework, hot and cold supply runs, radiator circuits — end feed is faster, cheaper per fitting, and produces a neater result than compression.

The requirements are straightforward: clean pipe ends (deburr and clean with wire wool or emery cloth), flux applied to both the pipe and inside the fitting, and correct torch technique. An end feed joint done properly is as reliable as the pipe itself. Done wrong — incomplete wetting, overheating, oxidised surface — it will leak eventually.

The Embrass Peerless Fusion End Feed Coupler 15mm x ½" is one of the most frequently purchased fittings we stock — it connects 15mm copper pipe to a ½" BSP male thread, used for everything from valve connections to tap tails and radiator valve bodies. The Fusion range from Embrass Peerless is WRAS-approved and kite-marked to BS EN 1254-1.

For standard 15mm-to-15mm copper pipe joints, the Atomic End Feed range covers the full set of fittings — couplers, elbows, tees, street elbows, and reducers — in a reliable bulk-buy format. The Atomic EF Obtuse Street Elbow 45° 15mm (25-pack) is a trade-counter staple — the 25-pack format is the practical way to buy when you're doing a full heating or pipework installation.

When to Use Compression Fittings

Compression fittings exist for specific situations where soldering is impractical or prohibited:

No torch access or fire risk

Inside stud walls with insulation, under timber floors in occupied properties, near gas pipes or other flammable material — anywhere you can't safely operate a blowtorch or where the risk of scorch damage is real, compression is the correct choice. Building insurers and building control officers increasingly scrutinise soldering near combustible materials.

Live or damp pipework

You cannot solder a joint with any water in the pipe — the steam prevents the solder from flowing properly. On a repair job where the system can't be fully drained, or where residual moisture is unavoidable, compression lets you make a joint without the water issue. This is one of the most common reasons to reach for compression on a repair or service job rather than an install.

Temporary or serviceable connections

Where you need the ability to undo the joint later — a meter connection, a test point, a temporary bypass — compression allows disassembly. The olive will have deformed and will need replacing if the joint is remade, but the fitting body itself can be reused.

Mixed material connections

Compression fittings are the standard connection method when joining copper to chromed pipe, copper to lead, or copper to stainless — materials where soldering is more difficult or not suitable.

Cost Comparison: End Feed vs Compression

End feed fittings are significantly cheaper per unit than compression. A 15mm end feed straight coupler costs a fraction of the equivalent compression coupler. On a full heating installation with 100+ fittings, this difference adds up substantially.

The trade-off is the cost of the tool (torch, solder, flux) and the time overhead of soldering each joint. For an experienced plumber doing volume work, end feed is clearly more economical. For a one-off repair or awkward location where compression is genuinely easier, the higher fitting cost may be justified by the time saved.

Compression olives are a consumable cost to factor in — the Embrass Peerless Compact Compression Olives 15mm (100-pack) is the economical way to keep olives in stock rather than buying them singularly. Copper olives are preferred over brass for softer pipe — they compress more evenly and are less likely to deform the pipe on tightening.

Common Mistakes on Both Systems

End feed errors

• Soldering a wet pipe — any residual water will cause a failed joint
• Overheating — burnt flux, oxidised copper, solder that balls up rather than flowing
• Under-fluxing — flux is essential, not optional. Apply to the pipe OD and the fitting socket
• Not deburring the pipe end — swarf inside the pipe, and the burr prevents full seating in the fitting

Compression errors

• Over-tightening — you only need 1¼ turns past hand-tight on a standard compression fitting. More than that risks splitting the fitting body or splitting the olive through the pipe wall
• Missing or misaligned olive — always slide the olive onto the pipe before the nut, and ensure it's seated squarely
• Re-using a deformed olive — olives are single-use. Always fit a new one if remaking a joint

What We Stock at APM Electricals, Acton

We carry the full Embrass Peerless Fusion End Feed and compression fittings ranges, plus Atomic End Feed in trade packs — all available for same-day collection from the trade counter at 24 Western Avenue, Acton, London W3 7TZ. Open 7 days. Call 020 8702 8080 to check stock or confirm availability before you come in.