What Is Part Exchange on a House?

Part exchange is where a new-build developer buys your existing home so its value goes straight towards your new house, letting you move without a chain. In practice you are usually offered around 90% of your home’s market value, sometimes 80% to 90% and occasionally close to full value on a home in high demand, and the whole thing can complete in weeks rather than months. To qualify, your current home normally has to be worth no more than about 70% of the price of the new build, and it needs to be a standard, easily resold property in good condition. You trade a slice of price, and the freedom to buy any home you like, for speed and certainty.

What is part exchange on a house?

Part exchange, often shortened to “part ex” or “PX”, is a scheme offered by new-build developers. Instead of selling your current home on the open market and hoping a buyer appears before your new house is ready, the developer takes your existing property in part payment for the new one. The equity you hold in your old home is applied to the purchase price of the new build, and you make up the difference with savings and a mortgage.

The usual comparison is trading in a car. You drive onto the forecourt, the dealer values your old car, knocks that figure off the price of the new one, and you drive away in the replacement without ever having to find a private buyer for the old vehicle. Part exchange does the same for houses. The convenience is real. So is the trade-off, because a dealer never pays you top price for the car you are trading in, and a developer will not pay you top price for the house either.

How does part exchange work, step by step?

The process is more structured than a normal sale, and the developer runs most of it:

1. You reserve a new-build plot. Part exchange only exists to sell the developer’s homes, so it starts when you find a plot you want and ask whether part exchange is available on it.
2. The developer commissions valuations. They instruct two, sometimes three, independent estate agents or RICS surveyors to value your current home. This is meant to be arm’s length, though the developer chooses who to ask.
3. You receive an offer. The developer makes an offer based on those valuations, typically at or slightly below the average figure. This is usually around 90% of market value, though it varies with condition, location and how easily your home will resell.
4. You accept or decline. There is little room to haggle. You either take the certainty on offer or walk away and sell the normal way.
5. Both sales run in parallel. Solicitors handle the legal work on your old home and your new one at the same time, and you sort your mortgage on the new build.
6. You complete, chain-free. Because the developer is your buyer, there is no chain behind you and completion often lands within a few weeks.

Throughout, you usually stay in your existing home right up to the day you move into the new one, which removes the classic new-build headache of selling too early and needing somewhere to live in between.

What percentage of market value will you actually get?

This is the number that decides whether part exchange is worth it, and it is where the marketing gets vague. Realistically, offers land between 80% and 90% of open-market value. A tidy, mainstream home in an area with strong resale demand might be offered closer to 90% or, occasionally, near full value if the developer is keen to shift a plot. A dated home, or one in a slower market, will be offered less because the developer has to factor in the cost and risk of reselling it.

Two things work against your price. First, the offer is built from valuations the developer commissioned, and surveyors valuing for a quick, guaranteed purchase tend to be cautious. Second, there is no negotiation. On the open market a keen buyer might push above the asking price in a competitive situation; in part exchange, the figure is the figure.

Treat the developer’s valuations as a starting point, not gospel. Get your own independent valuation first, so you know what your home is genuinely worth before you judge their offer.

Before you sit down with any developer, get a clear, independent read on your home’s value using our house valuation guide and free valuation tool. Walking in knowing your number changes the whole conversation.

Who qualifies for part exchange?

Part exchange is not open to everyone, and the rules are set by the developer, not by you. The two big tests are value ratio and saleability.

On value ratio, your current home usually has to be worth no more than around 70% of the price of the new build you are buying. The developer wants you trading up, because the point of the scheme is to sell you a more expensive home. As a rule of thumb, Taylor Wimpey has typically required your home to be worth no more than 70% of the new one, and Persimmon has looked for existing homes worth under 75% of the new purchase. If your current home is worth almost as much as the new build, part exchange usually will not be offered.

On saleability, developers want standard, mainstream homes they can resell quickly and without fuss. That generally means good condition and conventional construction. Homes that are often excluded include:

• Flats and leasehold properties with short leases or high service charges.
• Non-standard construction, such as concrete, steel-frame or timber-frame homes.
• Properties needing significant repair or modernisation.
• Homes with legal complications, structural issues or anything that makes a fast resale unlikely.

If your home is one of these, part exchange will probably be off the table, but a specialist cash purchase may not be, since cash house buyers routinely take on exactly the properties developers turn away.

The pros and cons of part exchange

Pros	Cons
No chain, so no waiting for a buyer	You typically get 80–90% of market value, not full price
A guaranteed buyer and a fixed timeline	You can only buy from that one developer
No estate-agent fees on your old home	New builds often carry a price premium
You can usually stay put until moving day	Little or no room to negotiate the offer
Less stress and paperwork than a normal sale	Strict eligibility rules exclude many homes

Part exchange vs the alternatives

Part exchange is one of several ways to move without the agony of a chain. It helps to see it beside the others.

	Open-market sale	Part exchange	Assisted move	Vetted cash sale
Likely price	Full market value	~80–90%	Near full value	80–92%
Chain risk	High	None	Lower	None
What you can buy next	Anything	That developer only	That developer only	Anything
Typical speed	3–6 months	Weeks	Varies	~27 days
Agent fees	You pay	None	Often covered	None

The striking thing is how close part exchange and a vetted cash sale are on price. Both land in roughly the same band. The real difference is freedom: part exchange ties you to buying one developer’s new build, while a cash sale hands you the proceeds to buy whatever you like next, including an established home that is not carrying a new-build premium. If speed and certainty are what you are after but you do not want a new build, compare the routes in our guides to cash house buyers and what percentage of value cash buyers pay.

A worked example

Say your home is worth £250,000 on the open market and you want to buy a new build priced at £375,000. Your home is comfortably under the 70% ratio (£250,000 is 67% of £375,000), so you qualify.

The developer’s valuations average £245,000, and they offer 90% of that: £220,500. You have saved roughly £4,000 in estate-agent fees, but you have accepted about £29,500 less than your home’s open-market value. Now weigh the other side of the ledger: no chain, no six-month wait, no risk of a buyer collapsing, and no double mortgage while you tried to time two sales. For someone who needs certainty, or who was facing carrying costs on two homes, that £29,500 can be money well spent. For someone with time and a saleable home, it is a steep price for convenience.

Which developers offer part exchange?

Most of the large national housebuilders run a part-exchange scheme on at least some of their plots, including Barratt, Taylor Wimpey, Persimmon, Bellway, Redrow, Bloor and Miller Homes, among others. Some run it in-house; many use a specialist part-exchange or quick-buy company behind the scenes to value and take on your old home. The details differ from builder to builder and from development to development, so two rules apply everywhere. First, part exchange is never guaranteed on a given plot, because the developer decides scheme by scheme. Second, the terms, the value ratio and the incentives are all set by that developer, so the offer you get from one builder tells you little about what another would say. Always ask, plot by plot, and get the specific terms in writing rather than relying on a brochure headline.

How does part exchange work with your mortgage?

Part exchange changes how you sell, not how you borrow. The equity in your current home, which is its agreed value minus whatever you still owe on your mortgage, becomes the deposit on the new build. You then take a new mortgage to cover the gap between that deposit and the price of the new home, and you still have to qualify for it on income and affordability like any other borrower.

Two points catch people out. If you are still inside a fixed-rate deal, redeeming your existing mortgage may trigger an early-repayment charge, so ask your lender whether you can port the deal to the new property instead. And because a developer’s offer is usually below open-market value, the equity you release is smaller than it would be from a full-price sale, which means a slightly larger mortgage on the new home. Factor that into the affordability sums before you commit, not after.

What does part exchange actually cost you?

On paper the fees look attractive. You pay no estate-agent commission on your old home, the developer normally pays for the valuations, and some builders contribute towards your legal fees or throw in moving costs. Compared with a standard sale, the out-of-pocket costs are genuinely low.

The real cost is not a fee at all. It is the gap between the developer’s offer and what your home would have fetched on the open market, which on our worked example above was around £29,500. That is the number that matters, and it dwarfs the few thousand pounds you save in commission. When a salesperson stresses the “no fees” angle, gently steer the conversation back to the offer figure, because that is where the money actually moves. Judge a part-exchange deal on the price gap and the new-build price together, never on the fee saving alone.

The catches and red flags to watch

Part exchange is a legitimate, well-established scheme, but go in with your eyes open:

• The new-build premium. New homes often sell at a premium to comparable older properties, and some of that premium can evaporate the moment you move in. If you are being offered 90% for your old home but paying a 10% premium on the new one, the convenience has cost you twice.
• You are locked to one seller. Once you are in a part-exchange deal you can only buy that developer’s home. That removes your leverage to negotiate the new-build price.
• Cautious valuations. The offer rests on valuations the developer arranged. Always get your own independent figure to sense-check it.
• Incentives can be smoke. A developer might dress up a middling part-exchange offer with “free” extras like flooring or stamp-duty contributions. Add up the cash value and compare it against the price gap, rather than being swayed by the word free.

When part exchange is a good idea, and when it is not

It suits you if you have specifically set your heart on a new build, you value certainty over squeezing out every last pound, your home fits the eligibility rules, and you want to avoid the stress of chains and viewings. For a family that needs to move by a fixed date, or anyone who cannot risk a sale falling through, that peace of mind is worth real money.

It is the wrong move if you want to buy an established home rather than a new build, if your home would sell well and quickly on the open market anyway, or if the price gap is simply too big to stomach. And it is unavailable entirely if your home does not meet the criteria. In those cases you have better options. An assisted move, where the developer helps sell your home on the open market so you get closer to full value while still securing the new build, keeps more of your price. A fast cash sale gives you similar speed to part exchange without tying you to one developer. And if you simply want the best price and have time, a well-run open-market sale, using the right agent from our comparison of house-buying options, will usually net you the most.

For a deeper look at the developer schemes specifically, our companion guide on the new-build part-exchange scheme goes further into the individual builders’ terms.

Is part exchange the same as an assisted move?

No, and the difference is worth money. With part exchange, the developer buys your home outright at a discount. With an assisted move, the developer does not buy your home at all; instead they arrange and often pay for an estate agent to sell it on the open market for you, while reserving your new build in the meantime. The upside of an assisted move is that you aim for close to full market value rather than accepting 80% to 90%. The downside is less certainty, because you are still relying on a real buyer being found before the developer’s deadline. If your home is likely to sell well but you still want the new build held for you, an assisted move often keeps more of your equity than part exchange does. Weigh the two side by side rather than assuming part exchange is automatically the simpler choice.

Your part-exchange checklist before you sign

Run through this before you commit to any part-exchange deal:

• Get an independent valuation of your current home first, from an agent with nothing to gain from the new-build sale.
• Ask for the offer as a percentage of that independent value, so you can see the discount clearly.
• Check the new-build price against comparable resale homes nearby, to spot any premium.
• Add up every incentive in cash and set the total against the price gap. Ignore the word free.
• Confirm your mortgage, including any early-repayment charge and whether you can port your existing deal.
• Read the eligibility and completion terms in writing before you rely on the move happening.

Do those six things and you will know, in pounds, exactly what the convenience is costing you, which is the only honest way to decide whether part exchange is the right move or whether an assisted move, a cash sale or a straightforward open-market sale would serve you better.

Frequently asked questions

What is part exchange on a house?

It is a scheme where a new-build developer buys your existing home and puts its value towards the price of the new one, so you move chain-free without finding a separate buyer.

What percentage of market value do you get on part exchange?

Usually around 80% to 90% of open-market value, set by averaging independent valuations the developer commissions. In-demand homes can be offered closer to full value; dated or hard-to-sell homes get less.

Do I qualify for part exchange?

Generally your home must be worth no more than about 70% of the new build’s price and be a standard, saleable property in good condition. Short-lease flats, non-standard construction and homes needing work are often excluded.

Is part exchange a good idea?

It is if you want a specific new build and value certainty and speed over price. It is not if you want to buy an established home, your property would sell well anyway, or the discount is too large.

How long does part exchange take?

Because there is no chain, it often completes within a few weeks of your offer being agreed, far quicker than a typical open-market sale of three to six months.

Can I part exchange my house for any home?

No. Part exchange only applies to new-build homes from developers who offer the scheme. To buy an established home chain-free, a cash sale is the closer equivalent.

Is part exchange better than selling to a cash buyer?

On price they are similar. The difference is choice: part exchange ties you to one developer’s new build, while a cash sale gives you the proceeds to buy any property next.

Wondering whether a part-exchange offer really stacks up? Get a free, no-obligation valuation and a genuine cash comparison at Ready Steady Sell, so you can judge the developer’s figure against what your home is truly worth.