Navien UK Avis 

I called the company as my boiler wasn't working it had an error report. My local heating engineer, who is excellent said
the problem needed done under the warranty. The boiler is 6 years old with a 10 year warranty. No one could come for a week. This was in December and snowing. I live in the country in Aberdeenshire and on my own.Nearest service engineer is Glasgow.
When he came he constantly complained about the state of the boiler. He arrived at 1.30pm and needed to be home at 6.30. It's a 3 hour drive. Not my fault. I had it serviced a month prior to the visit. He headed off said it was fixed. It wasn't, I phoned him and he came back. Not happy. 45 minutes later he left. Still not working. He showed me to press a switch inside the boiler, it's an outdoor boiler. It stayed on 5 minutes and went off again. I phoned and he told me to get my engineer to sort it. At my expense of course. Warranty not worth the paper it's written on.
I contacted my engineer and asked him to quote me for a new boiler. A reliable one with local workforce. 3 days later he fitted it. A Grant combi boiler. Fabulous. My house has never been so warm. Navien is total rubbish with very poor non existent back up. Avoid at all costs.

I emailed Navien after they commented on my review saying I would like to discuss further. To date, 8.2.2026 I have not had a reply to my email. Sounds about right!!!On 16th February still no contact from Navien!! True to form sadly. Avoid this company!!

The boiler was repaired under warranty which was great. The engineer was very knowledgeable and the job was completed quickly. The only slight niggle was that it took a week to get him there and while we had not moved in and wasn’t a major problem if we were living there it would’ve been a major headache.

I needed to report a hot water issue and got a call back within minutes of contacting the installation company. Aubrey at Navien was wonderful; extremely helpful and so pleasant to talk to. Thank you !!

Bought a Navion Boiler last year as was promised they were a good quality boiler .......I was pleased with it u till 2 days ago when it lost pressure and would not fire for either hot water or the heating. Was passed on to Navion custo er service as it has a 10 year warranty.......however it will take a week for an engineer to come out. No hot water or heating for this time in mid winter with the cost of 5 snd a half grand to have it installed.....and the customer service attitude seems to be I should be grateful they are coming out at all as 'they are not a service company'......makes you wonder how valuable that 10 yr warranty really is?! Wish I'd stuck with my gut and bought a Worcester Bosch!

Wow!

Where to start… I suppose context first!

We had a Navien boiler fitted via Boxt in Feb 2025.

It broke January 2026.

We have been without reliable heating or hot water for a week now, this includes 1 telephone visit and 1 engineer visit.

Currently heating starts, makes a rather disturbing noise, error messages and lights, before shutting off, cooling down and starting again on a 4 hour cycle….

Boxt were appalling ( with the exception of a couple of engineers) their customer service really ended with, “Just call Navien yourself “

So I Did

My God, it’s the most frustrating conversations I’ve ever had. I think I spoke to 3 different individuals throughout the week. So let’s go through them individually…….

Customer service rep 1.
Just plain rude, absolutely rude! However engineer booked in relatively acceptable time for a Saturday. I’m not unreasonable and appreciate weekend work

Engineer 1
Talks us through fixing it over the phone, twisting various knobs…. Unsurprisingly it broke again almost immediately

Engineer 2.
Lovely chap. Replaced a part on the boiler, but it broke again very quickly only this time it lost power too. He also reported the thermostat to Boxt

Boxt engineer brought a new thermostat and tightened some screws on the boiler and power was returned… it still doesn’t work, but at least there are some pretty lights to look at.

Customer service rep 2
Insinuating from the information from engineer 1 the broken boiler was our fault, and we should be grateful for all help.

Customer service rep 3
Attempted escalation to get a third visit to fit in with our schedule rather than theirs…. I very much doubt this happened.

The third visit will occur 3 days after the call was raised, require me to take a 3rd afternoon off work. A total of 7 days without reliable hot water or heating

I have probably spent as long chasing issues with both Boxt and Navien as I have in my full time job ( ok that’s an exaggeration but I’m pretty cross still so forgive me).

I thought Boxt were one of the worst customer experiences I’d ever had, then I spoke to Navien.

My only advice is don’t even consider a Navien heating system. Especially if you are Elderly or vulnerable, or acting on behalf of elderly relatives. Please don’t risk it, I’m middle aged relatively well and active. But I’m cold and unable to bathe or wash up without boiling a kettle or wash and dry my uniforms for work. I still think over a week for a boiler repair is unacceptable, particularly in January. But I’m particularly worried for those prone to hypothermia, or to vulnerable to survive without these common amenities. These people exist, I work with them.

As a result of the poor care, and absence of conscience, professionalism, or duty of care displayed by Navien I hope Boxt stop using them.

I work in a public service role, by taking repeated afternoons away from work, to allow for Naviens incompetence has affected many people, not related to my boiler. It must be understood that as customers we still have lives to lead, commitments to fulfill and jobs or roles in society. It shouldn’t be expected that customers drop everything repeatedly to allow engineers to fix problems that shouldn’t exist to begin with. As customers these issues should be fixed at our discretion not the company at faults.

This is Navien/Boxts problem, caused by either poor installation or poor products compounded by poor customer management. The effects are felt by not only myself, but my family and the public I represent in my professional role. Simply unacceptable.

I’m sure the response will be something to do with the number of engineers available, short notice etc. I do not accept this. There are many local engineers, we know subcontractors are used.

In summary don’t, please just don’t I suspect although can’t prove I’ve been misled, compounding generic poor if not unethical service and rude public facing service staff…..

Not really the magic formula is it

I chose Navien believing the warranty would protect homeowners if something went wrong. When our tankless water heater failed, I learned how difficult it actually is to access that warranty.

Navien refused to communicate with me as the homeowner and would only speak with licensed contractors on site. To pursue warranty support, I had to hire a plumber, an electrician and a general contractor—not primarily to repair the unit, but simply to act as intermediaries with Navien. They spent hours on hold, repeating basic troubleshooting steps, taking photos, and submitting documentation.

Despite this, Navien repeatedly deemed the information insufficient and imposed additional, sometimes contradictory requirements. Promised callbacks did not materialize. Documentation submissions were rejected or routed into procedural dead ends. Instead of progressing toward resolution, the process repeatedly reset.

In total, I spent more than five contractor hours and over $500 simply trying to access the warranty. Only after significant escalation did Navien agree to replace a single internal component rather than the unit.

The issue is not that a part failed—it’s that the warranty process appears structurally designed around contractor gatekeeping, prolonged delays, and escalating procedural hurdles that shift cost and effort onto the homeowner.

After reading other customer accounts, it’s clear this is not an isolated experience.

My conclusion: Navien may sell advanced products, but their warranty is effectively out of reach for most homeowners. If you are considering Navien, understand the real risk may not be the hardware—it may be the process required to make the warranty usable. I'll not make that mistake again with Navien.

Fast response to fix the problem, parts fitted at visit, very happy with the service! Thankyou

The engineer solved the problem straight away. However, the customer service by Navien is appalling. We didn't receive the promised call back when we reported our issue. When we rang again, we were told the engineer would be round on a particular day and then they did not turn up. The appointment was changed automatically to the next day without asking whether we would be available, so that meant we had to call yet again. Once rearranged, despite having text confirmation that the engineer would be round in the morning, he arrived in the afternoon around 2pm without any communication. As a result my partner has lost a day and a half of work waiting for an engineer to turn up.

Navien responded to our boiler problem immediately and the warranty repair was expertly carried out by KC Heating.

We had a problem with our boiler here in South Wales and the engineer Craig (didn't get his surname) from Bristol was fantastic. Our boiler wasn't fitted or serviced correctly by a third party which caused the fault. Craig identified the issues, explaining the problems and then sorted the repair. I was kept well informed and able to contact Craig directly as and when needed. Will be getting Craig back going forward!

Reason the review is not 5 stars is because the customer service phone line was a challenge. I was promised a call back with an update and received nothing multiple times. I had to chase and chase to get someone out to see my boiler. This was especially frustrating due to the weather being in the negatives at the time. That being said I would still recommend Navien but that is because of Craigs customer service and his professionalism.

Professional service. Super friendly engineers . Quick response to call out .excellent comunication throughout .

This is the worst product support and customer service I have encountered in the heating market.

I installed Navien oil boilers in two rental properties, and they have proven to be unreliable, overly sensitive, and fundamentally unsuitable for a rental environment. Faults are frequent, and the systems lack the robustness one would reasonably expect from a boiler marketed for domestic use.

The after-sales support is equally poor. Customer service appears to be outsourced, and frontline staff are unable to provide meaningful technical assistance or connect customers to the UK-based technical team. As a result, resolving even basic issues becomes unnecessarily time-consuming and frustrating.

Based on my experience, I would strongly recommend avoiding this company. The products are unreliable, and the lack of competent, accessible technical support makes ownership a continual problem rather than a solution.

Worst company ever, bought brand new boiler and had 2 times a fault, phone to the company and they sent me a guy who took 5 days to repair the boiler, left me without hot water. Put a complaint on and they never answer or reply, if you try to speak to someone is impossible that nobody cares. Worst experience ever

Very difficult to decide how many stars to give this rating as, have to say, we have had endless problems with our Navien boiler and would never buy another but, credit where credit is due, I cannot speak highly enough of Andy Butcher who is an absolute expert and always knows how to rectify any issue we experience, wouldn’t have anyone else through the door. Fingers crossed we get through to our next service without anything going wrong. Well done Andy for alerting us to the fact our thermostat needed replacing, which we’ve now done, problem solved, you are a superstar.

Well I wouldn't buy another. Ours is two years old and last year had problems with water pressure in the boiler continually dropping causing it to cut out and refuse to restart.
12 months on we have problems again and are awaiting a replacement part. Oil boilers used to be be so reliable. Not so with this one.

customer service/technical department
6 january 8 am
I contacted navien customer services to report a problem with my hot water getting cooler as it came out of the taps. I was told that I needed to speak to the technical department. After 20 minutes of waiting to be connected I put the phone down.
I then reported the problem on their website.
8 Jan 8 am
I phoned the customer service again. The assistant tried to get in touch with the technical department but without success and told me that she would keep trying and ring me back later on that morning.
No phone call.
early pm I sent 2 emails (info@navien and service@navien) to explain my problem again and my dissatisfaction.
9 Jan pm
Still no phone call or email from navien.
My boiler is only 3 years old and under warranty but navien does not seem to be interested in fixing the existing problem. Breach of contract?

12 Jan
The engineer (from British gas) turned up and felt that a new plate was required. He did not have one, As there was 1 in stock, he could do the job the following Monday. He had to persuade his manager that a new part was required.
19 January
The same engineer turned up. When I asked him how long the job would take, he told me that he did not know as he was not conversant with navien boilers and that he had not done this kind of job before.
He replaced the plate, drained the waterfrom the system and told me it was now working properly. It was not as the hot water soon cooled as it was coming out of the tap. He had to get in touch with his manager several times for advice/instructions.
He relayed to me what his manager has said:
- The cold water coming into the house was very cold!! It was not a problem during the last 3 winters.
- The tap should not be full on when running a bath - once again not a problem before.
- There was nothing wrong with the boiler and the drop of temperature was quite normal.
After several hours and a vast amount of water wasted down the drain, he told me there was nothing he could do to sort the problem and left.
I perfectly know that there is a problem. Nothing has changed in the house since the installation of the boiler but its performance has deteriorated.
I'm not too impressed with the feeble excuses I was given and being told that everything is working perfectly.

New boiler installed. Installer failed twice to fix low pressure problem. Called Navien Custoner care who were great. John went above and beyond attended next morning (Sat). Sourced problem to leak in radiator pipe. He was very kind and reassuring to a worried 72 year old lady. He is a definite asset to Navien whom i found to be a very reliable company. I live in the Edinburgh area.

Major problems on and off for over 3 months with my Navien unit. On 28th December 2025 my Combi Boiler failed completely. The unit was only installed in July 2025. I have to say it was installed by another company BoxT. I have to say Navien didn't get involved until the 28th December. Navien supplied a engineer on the 30th December, unable to fix unit without replacing a part. Engineer did not have the part, I have to ask why it needs a new part if only installed in July 2025? I have been without heating and hot water now for over 7 days in the coldest days of this winter. My wife and I are both 79 so its been very difficult. Still not fixed going into 8 days

I was transferred to technical support, after 20 minutes no one picked up.

As an installer , I have fitted 30+ boilers in the past year, I have a customer that has had no hot water for 3+ weeks, we have no local representative.The last rep left about 4/6 months ago, how hard can it be, to replace a rep ??