diff --git a/lib/errors/spec.js b/lib/errors/spec.js
index 81a3e2f..c7adece 100644
--- a/lib/errors/spec.js
+++ b/lib/errors/spec.js
@@ -85,8 +85,14 @@ module.exports = [{
     name: 'InvalidSatoshis',
     message: 'Output satoshis are invalid',
   }, {
-    name: 'FeeError',
-    message: 'Fees are not correctly set {0}',
+    name: 'SmallFeeError',
+    message: 'Fee is too small: {0}',
+  }, {
+    name: 'LargeFeeError',
+    message: 'Fee is too large: {0}',
+  }, {
+    name: 'DifferentFeeError',
+    message: 'Unspent value is different from specified fee: {0}',
   }, {
     name: 'ChangeAddressMissing',
     message: 'Change address is missing'
diff --git a/lib/transaction/transaction.js b/lib/transaction/transaction.js
index 145f8b0..8729557 100644
--- a/lib/transaction/transaction.js
+++ b/lib/transaction/transaction.js
@@ -203,16 +203,16 @@ Transaction.prototype.getSerializationError = function(opts) {
   var isFullySigned = this.isFullySigned();
 
   if (!opts.disableDifferentFees && feeIsDifferent) {
-    return new errors.Transaction.FeeError(feeIsDifferent);
+    return new errors.Transaction.DifferentFeeError(feeIsDifferent);
   }
   if (!opts.disableLargeFees && feeIsTooLarge) {
     if (missingChange) {
       return new errors.Transaction.ChangeAddressMissing('Fee is too large and no change address was provided');
     }
-    return new errors.Transaction.FeeError(feeIsTooLarge);
+    return new errors.Transaction.LargeFeeError(feeIsTooLarge);
   }
   if (!opts.disableSmallFees && feeIsTooSmall) {
-    return new errors.Transaction.FeeError(feeIsTooSmall);
+    return new errors.Transaction.SmallFeeError(feeIsTooSmall);
   }
   if (!opts.disableDustOutputs && this._hasDustOutputs()) {
     return new errors.Transaction.DustOutputs();
@@ -226,27 +226,28 @@ Transaction.prototype.getSerializationError = function(opts) {
 };
 
 Transaction.prototype._isFeeDifferent = function() {
-  var fee = this.getFee();
-  var unspent = this._getUnspentValue();
-  if (fee !== unspent) {
-    return 'Unspent value ' + unspent + ' is different from specified fee ' +
-        fee + ' and no change address is specified';
+  if (!_.isUndefined(this._fee)) {
+    var fee = this._fee;
+    var unspent = this._getUnspentValue();
+    if (fee !== unspent) {
+      return 'Unspent value is ' + unspent + ' but specified fee is ' + fee;
+    }
   }
 };
 
 Transaction.prototype._isFeeTooLarge = function() {
-  var fee = this.getFee();
+  var fee = this._getUnspentValue();
   var maximumFee = Math.floor(Transaction.FEE_SECURITY_MARGIN * this._estimateFee());
   if (fee > maximumFee) {
-    return 'Fee is too large: expected less than ' + maximumFee + ' but got ' + fee;
+    return 'expected less than ' + maximumFee + ' but got ' + fee;
   }
 };
 
 Transaction.prototype._isFeeTooSmall = function() {
-  var fee = this.getFee();
+  var fee = this._getUnspentValue();
   var minimumFee = Math.ceil(this._estimateFee() / Transaction.FEE_SECURITY_MARGIN);
   if (fee < minimumFee) {
-    return 'Fee is too small: expected more than ' + minimumFee + ' but got ' + fee;
+    return 'expected more than ' + minimumFee + ' but got ' + fee;
   }
 };
 
diff --git a/test/transaction/transaction.js b/test/transaction/transaction.js
index f3ffbb3..cf8ff21 100644
--- a/test/transaction/transaction.js
+++ b/test/transaction/transaction.js
@@ -266,7 +266,7 @@ describe('Transaction', function() {
         .sign(privateKey);
       expect(function() {
         return transaction.serialize();
-      }).to.throw(errors.Transaction.FeeError);
+      }).to.throw(errors.Transaction.SmallFeeError);
     });
     it('on second call to sign, change is not recalculated', function() {
       var transaction = new Transaction()
@@ -332,7 +332,7 @@ describe('Transaction', function() {
         .to(toAddress, 40000000);
       expect(function() {
         return transaction.serialize();
-      }).to.throw(errors.Transaction.FeeError);
+      }).to.throw(errors.Transaction.LargeFeeError);
     });
     it('fails if a dust output is created', function() {
       var transaction = new Transaction()
@@ -372,7 +372,7 @@ describe('Transaction', function() {
         .sign(privateKey);
       expect(function() {
         return transaction.serialize();
-      }).to.throw(errors.Transaction.FeeError);
+      }).to.throw(errors.Transaction.DifferentFeeError);
     });
     describe('skipping checks', function() {
       var buildSkipTest = function(builder, check) {